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Port Dinllaen

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Re: Port Dinllaen

Unread postby kbarber » Tue May 13, 2014 11:05 am

Hello Adam, I hope you'll indulge a little rather radical thinking to see if anything comes of it?

Historically, I'd have been just a little surprised if the Cambrian had had such a welcome that it was invited to use the NWIR station, particularly as the site was cramped & difficult and there was no suitable platform on its side of the station. So was there initially a CR station somewhere in the vicinity of the carriage sidings, or even the goods in road/cattle dock? If so, there might be remains that were adapted for other uses once the interloper had finally been allowed to join in the big boys' game. Another place the CR station might have ended up was down the breakwater beyond the NWIR platform 1, approached more-or-less along the line of the Run Round or one of the carriage sidings. (The big boys might have considered that a suitable place of outer darkness for the interloper - not always a minor consideration.) That would mean separate station buildings to a different design alongside 1b. It would also almost certainly mean the CR had to build two signalboxes, one in the vicinity of the main station throat to work the connections with the NWIR station and another for the points between their platform and run round roads. At that stage there would be no connection between 1a nd 1b, and probably not even a continuous platform there. (A lot of money for minimal facilities, but why should that bother the incumbents who would be making the rules?) Eventually, of course, sanity prevailed and the platform lines were linked (a la Manchester Victoria/Manchester Exchange) but leaving the second approach to 1b along the RR. (All that certainly fits with your suggestion in your post of 3pm yesterday that the GW was made to put up with what the incumbent could be bothered to provide, except that all they provided was the most awkwardly constrained bit of land they could get away with leaving the CR/GW to fit in what they could.) It also perhaps explains why the goods yard has to be accessed across the GW approach, but it's likely to mean that there is only one access which (when built) would've been as close to the signalboxes as possible - there would have had to be a CR box around the east end of the throat and a NWIR one not too far from it, with complications of bolt releases between them to give what would effectively have been dual control of several sets of points.

Like Mike I'd expect the GW to have a separate MPD. I'm not sure BGP is an appropriate reference here, I guess the sheds there were MR and S&D, in which case you have a degree of common ownership that wouldn't exist at PD. The branch sounds a very reasonable place to put a GW shed and I'm afraid my instinct is that it would fit rather nicely where you have the quarry. That would certainly add to the interest of through trains, with either the inward or forward loco having to cross the whole layout from the branch to P4 or Goods Out road. If the site is actually that physically constrained (a wall of granite so it has to be a quarry not a shed) I'd be looking to put the GW MPD offstage further along the branch, probably with a box controlling access from the single line. Initially there would've been some sort of staff or token working, of course, but the buildup of traffic might have led to the section being controlled just by signals. I'm not sure whether Direction Lever might have been considered appropriate in this situation (perhaps JRB would be able to advise what the criteria were for that to be an acceptable method of working). But if not the GW did use its own design of single line lock-&-block instruments (several sections in the Malvern area) and that might have been very suitable for a situation where there were frequent locos on & off shed to be fitted between the procession of holiday trains. Any kind of physical authority for the single line would be a major pain in the proverbial in that situation! Assistance up the bank needs to be provided for as well. If the bank begins very close to PD I'd imagine passenger trains to the GW would just be double-headed. The alternative is that they have to stop in or just beyond the throat to take their banker or that the banker has to join them in the platform; I don't imagine the inward engine would be used as a banking engine, although I'm sure there were places where that did happen. If the bank started further out, the stop might well be at the GW shed but that, of course, would be offstage so wouldn't offer what you seek.

So what begins to crystallise in my mind is a layout where the main MR/GC lines pretty much run straight into P1 and P2 with the main diagonal connection(s) then running top left - bottom right to P4. The CR/GW would then enter pretty much along the Goods In which would line up with the RR to give access to 1b. That would mean running signals rather than shunts - and perhaps additional calling on signals as well - on & off the Run Round (together with releasing arrangements at the far end of 1b that would mirror those you provide for P4). But it's quite likely there would be no facing connection from the down LM/ER to the GW approach, although there might be an up direction connection from the GW approach to the up LM/ER. Connections to & from the shed(s) and goods facilities would then need to be added according to need. The highest doll on the branch home bracket would then be an additional leftmost one reading along the GW approach (present Goods In) towards 1b.

The original layout would probaby have had four boxes, the two CR/GW ones already mentioned (with the station end box having no connections to the NWIR lines) plus the main NWIR box controlling the throat and a secondary one at the station that would certainly be needed to work the P2/P3 connection and signals at least (it might also, as at Broad Street, work platform end signals both in & out and would undoubtedly have some control over the run round connections off 1 (later 1a) and 4. I say this because pointwork would have been clustered close to the locations of these boxes and that configuration might not change a great deal with the resignalling. (It rather depends just how much disruption the various railway/regional authorities were prepared to countenance when the resignalling took place.) Even in BR days there were intense regional rivalries and, given the joint nature of the operation that would set it apart from the owning railways, it's quite possible there would be some staff at PD who still considered themselves NWIR as late as the 1980s!

So far as the run rounds are concerned, I suspect the HH P3 layout dates from the 1970s remodelling. In the 1960s or earlier I'd expect to see your P4 run round controlled by a ground frame released from the box, with drivers trusted to stop clear of the crossover they needed to use. P1 would be rather more interesting. My surmise would be that when the 1a - 1b connection was put in, the GW Station box would be given a slot on the main running signals controlling the entrance to 1a so that a train wasn't admitted on a main aspect while the crossover was reversed against it. (Those signals would probably also be given warning arms, again with a slot from the GW station box, so a train could still be let in if the GW crossover was in use.) The discs at the crossover on the P1 line would be full-sized arms, with the 1b starter probably being a bracket to allow departures via 1a or the GW approach and both it and the 1a arrival signal having calling on arms so run rounds and shunts could take place with a train or vehicles in 1a or 1b. These signals and the crossover would all be worked by the GW station box (which might well need reframing to accommodate the additional functions and would end up with some kind of block working both to the main GW box along the GW approach and to the NWIR box along P1). All these signals would almost certainly be retained on resignalling with the crossover motorised and a full complement of warning and calling on arms - that would be the only way to achieve the necessary flexibility.

If you find yourself needing to economise on levers (the new box will be a big job!) it might be useful to surmise that the resignalling was an LMR job. The LM was big on signals selected by points and theatre-type indicators would fit that idea very well (though I fear you'd need to lose the branch bracket). But the ER might well have gone for an arm for each route at the inner home signals, hence a nice bracket at the NWIR inner home as well. Whether the discs would have route indicators (likely to be stencil type rather than theatre type) is uncertain. There are probably people here better able then me to say, but I have a suspicion the LM would have been more likely to use them than the (LN)ER.

I hope that little lot doesn't upset too many apple carts; better yet, perhaps it will start you thinking even more about what is being provided. This looks like a good scheme and I'd love to see what it looks like when it's built. If the whole station throat had been heavily remodelled your plan, subject to some of the comments others have made, might well have been the outcome so it could still be one to go with. But I'd suggest you need to look at P1 and P4 differently (hopefully my thoughts will be useful there).
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Re: Port Dinllaen

Unread postby Pete2320 » Tue May 13, 2014 12:00 pm

davidwoodcock wrote:
Mike Hodgson wrote: Yes, the main signal would have been fixed at danger, as there is no running movement beyond it. You have to have a main signal there because it's not allowed to have the previous running signal leading to only a shunt signal.


Wasn't the use of fixed semaphore stop signals a comparatively recent (say 1960s) feature that grew out of the introduction of fixed red+subsidiary colour light signals (which were definitely in use by 1960)?

I'd certainly go along with that
also wrote:I would have thought that earlier just a small-arm subsidiary signal would have been used, being cleared to permit the shunt movement instead of the dolly later provided.

Or a full size arm, cleared for what we would nowadays consider a subsidiary movement.
and also wrote:I seem to remember that Holyhead had somewhere in its layout the shortest arm LQ LNWR signal that I have ever seen which had just this sort of function.

Not the one I remember. That was a fully fledged running signal (platform starter?). The short arm was to give clearance to an adjoining line.

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Re: Port Dinllaen

Unread postby Chris Osment » Tue May 13, 2014 12:18 pm

>> I'm not sure BGP is an appropriate reference here, I guess the sheds there were MR and S&D, in which case you have a degree of common ownership that wouldn't exist at PD....

Indeed, that was the case :)
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Re: Port Dinllaen

Unread postby kbarber » Tue May 13, 2014 5:41 pm

I'm afraid I've had another thought.

1897 is rather early for the line from Aynho; the GW & GC Joint from Northolt Jc to Ashendon Jc didn't open until 1906 and Marylebone itself wasn't opened until 1899. So it would fit known railway history better if the Irish Extension opened sometime around 1908 - 10.

The date matters. Obviously the Irish Extension would bring considerable new traffic to the original B&I/NWIR lines, which might well need quite a bit of resignalling to meet this new demand. That, of course, was the period that the GCR was installing a good deal of power signalling worked by BPRS draw-slide frames. (See http://www.signalbox.org/gallery/e/hydejcn.php and http://www.signalbox.org/gallery/e/receptionsidings.php for examples.) So what's the likelihood that the Irish Extension was built with power signalling from the start and that the original NWIR was resignalled at the same time to cope with the extra traffic?

The GCR's Signal Engineer at the time was A F Bound, who had worked on the LSWR LP pneumatic signalling briefly in 1903 while employed by BPRS; he would have seen something of that company's automatic signalling between Woking and Basingstoke and it really isn't too much of a stretch to think he would have tried the same thing on the new line. Automatic signalling would have had considerable advantages on the original B&I line too, as it would allow far greater traffic to be worked by less signalboxes, perhaps no small consideration in the sparsely populated countryside of Snowdonia. It would also allow shorter sections on the fearsome climb from Bangor through Bethesda and on to Llyn Ogwen. We know that Bound was impressed by US practice so it's also likely that any sidings provided on the new and resignalled lines would be worked by ground frames interlocked with the new signals, further reducing the number of signalboxes required.

Port Dinllaen would probably need a degree of resignalling too, after all it would (hopefully) become the terminus of a much increased traffic from London and the Midlands. (So would Pont Llyni Junction, for similar reasons.) Again, it's not unlikely that a power scheme would be chosen. Although the new system allowed automatic signalling in open country, traditional block working tended to be retained where boxes were close together (as seems likely in the immediate vicinity of PD, where there's likely to be further yards, sidings, interchanges with NG lines from the slate quarries, etc).

So we can postulate a full resignalling taking place in about 1907, with provision of every modern appliance and a generous track layout in anticipation of the forthcoming traffic. Perhaps this was the time, too, when the Cambrian and the GC & Midland Joint integrated their two stations (as I mentioned in my previous post). That would have made things a lot easier for all concerned as it would allow the CR to close both their boxes (worth a contribution to the cost of resignalling) and improve the working of the station no end.

So far as the signalbox building was concerned, I have an idea that on joint lines it wasn't uncommon for one company to have responsibility for buildings while the other dealt with signalling equipment (or some other such split). So we could well have a (largish) Midland Railway box to house the draw-slide frame, which would be fairly visible through the windows.

During the decades of financial stringency that followed the Great War and extended into the 1970s and '80s, it is unlikely that PD would have been high on the list for resignalling. After all, the line was already fairly economical to work with its long stretches of automatic signalling, and power signalling at the main traffic nodes also kept the staffing requirement lower than at manually-worked stations. So the signalling at the date of the layout would be likely to consist of a mix of GCR lower quadrants and a few LNER upper quadrants worked from the power frame in a good sized MR box (possibly with its lower parts protected by a thick brick blast wall).

How does that little lot sound?
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Re: Port Dinllaen

Unread postby Pete2320 » Wed May 14, 2014 4:13 am

kbarber wrote:How does that little lot sound?

I love it :)

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Re: Port Dinllaen

Unread postby tynewydd » Wed May 14, 2014 5:14 am

kbarber wrote:Hello Adam, I hope you'll indulge a little rather radical thinking to see if anything comes of it?

Sure - the great thing about the current state is that apart form the outline and overall 21'x12' (with one side open) nothing is yet fixed. This is - as I can see from the inventiveness being shown on this board - a good thing!

kbarber wrote:Eventually, of course, sanity prevailed and the platform lines were linked (a la Manchester Victoria/Manchester Exchange) but leaving the second approach to 1b along the RR.

Ok - following along, so that would mean adding a linkage between the Gds In and the Pl1 RR, allowing a shorter -possibly 2 coach train stopping train to approach and depart 1b directly for the branch. Interesting.

Just as a historical note, the layout at HH had such a secondary station at the mail pier reached roughly along that approach. The idea, I think, was for the mail packets to be closer to Dublin by being directly in the outer harbour. Kind of the opposite reason but similar trackwork.

I guess from all these comments that the "through express" would have been welcome to arrive and depart from Pl4? After all, at least on departure to Caernarvon/Manchester it would be on the down LMS/LNE side. As I have half-drawn it now there is a sweeping curve leading from platform 4 that points directly to the branch... This enabled me to have the branch not have to have a tighter curve but start the main exit curve earlier allowing the branch

kbarber wrote:Like Mike I'd expect the GW to have a separate MPD. The branch sounds a very reasonable place to put a GW shed and I'm afraid my instinct is that it would fit rather nicely where you have the quarry.

So my problem with this is not the shed per se, substituting for a quarry is doable but the need to provision (presumably) a second turn-table. I don't have that room, or rather, I don't have room for more than a turntable or a shed. There is a rising branch line hidden behind and ~6" below that quarry right now that is connecting PLJ to Nantlle. And then the wall...

In the part of the plan you can't yet see, the MPD is constructed in the "efficient" large scale manner suggested by Harry and the late Ivor C. Marshall but with a second shed hanging off the turntable (and so gaining the advantage of a 90 degree turn "for free". I know that in BR days post war there was a move to upgrade sheds to make them less labor intensive. BGP, for example, seemed to have been rationalized versus the two different sheds with different turntables which I think existed prior.

kbarber wrote:That would certainly add to the interest of through trains, with either the inward or forward loco having to cross the whole layout from the branch to P4 or Goods Out road.

Yup - is it acceptable to have a single turntable and "efficient" facilities so locos can be fed and watered on the LMS/LNE but have them cross over to the "other side" to be merely stabled in the old GW shed? In particular bankers, and other WR stuff, for example?

kbarber wrote:I'm not sure whether Direction Lever might have been considered appropriate in this situation

I see I have some reading to do!

kbarber wrote:Assistance up the bank needs to be provided for as well. If the bank begins very close to PD I'd imagine passenger trains to the GW would just be double-headed. The alternative is that they have to stop in or just beyond the throat to take their banker or that the banker has to join them in the platform; I don't imagine the inward engine would be used as a banking engine, although I'm sure there were places where that did happen. If the bank started further out, the stop might well be at the GW shed but that, of course, would be offstage so wouldn't offer what you seek.


Agree on double-heading for all important passenger trains. If I change the gradients a bit, I can make the first part to beyond the "shed" be pretty flat. That way there could be signals for bankers from the shed. I assume that means a calling on signal so the banker can approach? The bank ends at Tan-Y-Graig which has a double-ended central road a la Evercreech for banking engines that arrived as LEs to wait for custom/run back to HH. But that's a later topic.

kbarber wrote:So what begins to crystallise in my mind is a layout where the main MR/GC lines pretty much run straight into P1 and P2 with the main diagonal connection(s) then running top left - bottom right to P4. The CR/GW would then enter pretty much along the Goods In which would line up with the RR to give access to 1b.

Amazingly that was what I was sketching out in response to John's observation about the misalignment of the main roads. I hadn't added in the idea of 1b access though.

kbarber wrote:That would mean running signals rather than shunts - and perhaps additional calling on signals as well - on & off the Run Round (together with releasing arrangements at the far end of 1b that would mirror those you provide for P4). But it's quite likely there would be no facing connection from the down LM/ER to the GW approach, although there might be an up direction connection from the GW approach to the up LM/ER. Connections to & from the shed(s) and goods facilities would then need to be added according to need. The highest doll on the branch home bracket would then be an additional leftmost one reading along the GW approach (present Goods In) towards 1b.

Yup - I'll try and get the roads right first and then I'll take all the comments about re-signaling in the light of the new plan. I am drawing in XTRKCAD in parallel because you can make vast changes easily in Illustrator that you have no ability to actually build...

kbarber wrote:I hope that little lot doesn't upset too many apple carts.

No - a little apple-cart upsetting is exactly why this is a valuable forum. Plus its only by this type of in depth discussion that one can learn anything useful.

I even like the comments about the name - it mirrors the comments between me and my Da about the same subject. As a 50% Welshman myself, but some one with only enough knowledge of the "Language of Heaven" to understand when I am being told not to park somewhere rather than I am stupid to try (Dim Parcio), or that a "Little House" (Ty Bach) might be something smelly in addition to diminutive, he (someone who is fluent) had a few choice words for the Victorians and their cluelessness.

Thanks again,
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Re: Port Dinllaen

Unread postby tynewydd » Wed May 14, 2014 6:07 am

kbarber wrote:I'm afraid I've had another thought.

1897 is rather early for the line from Aynho; the GW & GC Joint from Northolt Jc to Ashendon Jc didn't open until 1906 and Marylebone itself wasn't opened until 1899. So it would fit known railway history better if the Irish Extension opened sometime around 1908 - 10.


Quite right - faux history rewritten! Makes one feel almost Soviet...

I like the overall thinking, if this proves out then the Buckingham GCR (àla Denny) lineage of the scheme will have more than a virtual "tip o' the hat" to the Master. I get the key advantages, I think. You have bigger, fewer, boxes and you have economy in levers because you can do more with less - which makes running the show easier - with things like automatically resetting the signals to danger. And because you have older GC LQ and newer LNE UQ, and remaining GW LQ possibilities you have lots of potential variety. But still you get "traditional" block working because of close distances in this case.

You mention a "blast wall" around the lower part of the signalbox because of the presence of compressed air inside it, or as a protection for the sensitive equipment there against the gentle ministrations of the Luftwaffe?

kbarber wrote:How does that little lot sound?

Hmm. "Little" or "lot"? Surely the combo is an oxymoron!! You certainly have given me some good things to ponder - let me see if I can get a workable trackplan as amended to start with.

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Re: Port Dinllaen

Unread postby kbarber » Wed May 14, 2014 7:47 am

tynewydd wrote:
kbarber wrote:I'm afraid I've had another thought.

1897 is rather early for the line from Aynho; the GW & GC Joint from Northolt Jc to Ashendon Jc didn't open until 1906 and Marylebone itself wasn't opened until 1899. So it would fit known railway history better if the Irish Extension opened sometime around 1908 - 10.


Quite right - faux history rewritten! Makes one feel almost Soviet...

I like the overall thinking, if this proves out then the Buckingham GCR (àla Denny) lineage of the scheme will have more than a virtual "tip o' the hat" to the Master. I get the key advantages, I think. You have bigger, fewer, boxes and you have economy in levers because you can do more with less - which makes running the show easier - with things like automatically resetting the signals to danger. And because you have older GC LQ and newer LNE UQ, and remaining GW LQ possibilities you have lots of potential variety. But still you get "traditional" block working because of close distances in this case.

The bigger, fewer boxes would only exist at principal locations. The other advantage is no boxes at all for long distances in open country and far smaller boxes (physically, at least) at junctions and suchlike places. And perhaps boxes open 'as required' (a few hours a day, Monday - Friday only) at mid-sized stations that warranted regular service of a goods yard. (Reading that, I hope I haven't made the wrong assumption about what you're saying... apologies if so.)

I think, if the scenario I painted for pre-WWI resignalling had taken place, it's very unlikely there would have been any GW signals left at PD Station itself. If the MPD were far enough away to warrant its own box it would have GW lower quadrants (or possibly even some Cambrian LQs - I wonder how long some of them survived?) but the GC would've replaced everything worked by the new power frame.

tynewydd wrote:You mention a "blast wall" around the lower part of the signalbox because of the presence of compressed air inside it, or as a protection for the sensitive equipment there against the gentle ministrations of the Luftwaffe?

Reception Sidings (as linked to) had one, and one around the compressor house too. Yes, it was intended to inhibit Herr Hitler's dislike of fully-signalled stations, hence not unusual to find it was both rather heavy and very crudely built. At Crewe they took it further and built complete new signalboxes to an enhanced ARP specification but I'm not sure PD would've been considered to warrant such consideration. (Holyhead got no extra protection at all, although the fact it was a brick-built LMS design was surely relevant; I imagine it might have gained a blast wall had it been an all-wood structure.)
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Re: Port Dinllaen

Unread postby kbarber » Wed May 14, 2014 8:29 am

tynewydd wrote:
kbarber wrote:Eventually, of course, sanity prevailed and the platform lines were linked (a la Manchester Victoria/Manchester Exchange) but leaving the second approach to 1b along the RR.

Ok - following along, so that would mean adding a linkage between the Gds In and the Pl1 RR, allowing a shorter -possibly 2 coach train stopping train to approach and depart 1b directly for the branch. Interesting.

Actually I was thinking of 1b as a full-length platform, initially for the GW/Cambrian share of the mail traffic when their station was separate but obviously adding to the flexibility after integration.

tynewydd wrote:Just as a historical note, the layout at HH had such a secondary station at the mail pier reached roughly along that approach. The idea, I think, was for the mail packets to be closer to Dublin by being directly in the outer harbour. Kind of the opposite reason but similar trackwork.

I never knew that! Particularly interesting as my partner grew up just outside Holyhead and his nephew's first steps on the railway included some time acting as booking boy in Holyhead box!

tynewydd wrote:I guess from all these comments that the "through express" would have been welcome to arrive and depart from Pl4? After all, at least on departure to Caernarvon/Manchester it would be on the down LMS/LNE side. As I have half-drawn it now there is a sweeping curve leading from platform 4 that points directly to the branch... This enabled me to have the branch not have to have a tighter curve but start the main exit curve earlier allowing the branch

If you're saying what you suggested in your description of typical movements, then yes, that's exactly what I think. Again, it will certainly add to the interest as every through express will have to cross the entire throat at some point in its passage, as will either the inward or outward loco(s). Keeps the signalman busy (or, as Flanders & Swann put it, "It all makes work for the working man to do" :lol: )

tynewydd wrote:
kbarber wrote:Like Mike I'd expect the GW to have a separate MPD. The branch sounds a very reasonable place to put a GW shed and I'm afraid my instinct is that it would fit rather nicely where you have the quarry.

So my problem with this is not the shed per se, substituting for a quarry is doable but the need to provision (presumably) a second turn-table. I don't have that room, or rather, I don't have room for more than a turntable or a shed. There is a rising branch line hidden behind and ~6" below that quarry right now that is connecting PLJ to Nantlle. And then the wall...

Then perhaps the answer is an 'offstage' GW shed, with an advanced starter beyond the quarry siding to shorten the section a little further and some means of signals-only single line control to improve the throughput of traffic. I wonder if that might be supplemented by a loco holding siding (or even a small turnround servicing point, with water facilities and perhaps an ashpit) so GW locos waiting to take a through express forward could be brought down to the station before the train arrives from the Bangor direction?

tynewydd wrote:In the part of the plan you can't yet see, the MPD is constructed in the "efficient" large scale manner suggested by Harry and the late Ivor C. Marshall but with a second shed hanging off the turntable (and so gaining the advantage of a 90 degree turn "for free". I know that in BR days post war there was a move to upgrade sheds to make them less labor intensive. BGP, for example, seemed to have been rationalized versus the two different sheds with different turntables which I think existed prior.

kbarber wrote:That would certainly add to the interest of through trains, with either the inward or forward loco having to cross the whole layout from the branch to P4 or Goods Out road.

Yup - is it acceptable to have a single turntable and "efficient" facilities so locos can be fed and watered on the LMS/LNE but have them cross over to the "other side" to be merely stabled in the old GW shed? In particular bankers, and other WR stuff, for example?

Not so much whether it would be 'acceptable', more what the various companies (some at each others' throats at times) would have provided in the dim & distant. In a situation such as this, the Cambrian would undoubtedly have built its own shed. In fact it would probably have started with a very small shed as close to the station as it could get, then built a 'new' shed further out when the original became impossibly small. (Sudden thought: the old Cambrian shed would almost certainly have become the location of the holding siding/turnround servicing point when the new shed was built.) Even in the late 1950s/early '60s the GW Shed would be under entirely separate administration, with a BR shed code in the GW series (perhaps a sub-shed of Machynlleth) while the LM/ER shed would be in the LM series (possibly a sub-shed of Bangor but, for a location of this importance, more likely a principal shed in its own right). So whatever the LMS/LNE did to make their shed more efficient, the GW would be excluded from that particular party (and, being the GW, would definitely prefer it that way).

<snip>
tynewydd wrote:
kbarber wrote:Assistance up the bank needs to be provided for as well. If the bank begins very close to PD I'd imagine passenger trains to the GW would just be double-headed. The alternative is that they have to stop in or just beyond the throat to take their banker or that the banker has to join them in the platform; I don't imagine the inward engine would be used as a banking engine, although I'm sure there were places where that did happen. If the bank started further out, the stop might well be at the GW shed but that, of course, would be offstage so wouldn't offer what you seek.


Agree on double-heading for all important passenger trains. If I change the gradients a bit, I can make the first part to beyond the "shed" be pretty flat. That way there could be signals for bankers from the shed. I assume that means a calling on signal so the banker can approach? The bank ends at Tan-Y-Graig which has a double-ended central road a la Evercreech for banking engines that arrived as LEs to wait for custom/run back to HH. But that's a later topic.

It sounds as if you're saying double-heading plus a banker as far as T-y-G? If that were the case I'd anticipate the banker being attached in the station. So the length of platform beyond the crossover in P4 needs to accommodate both inward engines and the banker. The turnround point might then also become the place where bank engine(s) get held waiting their next work, as well as a place to stow forward engines. The sequence of operations for a through express to the GW is then:
1: forward engines arrive from the GW shed and are signalled to the 'Old Shed' (as the loco turnround point is known to everyone at PD - its official name, as shown on the SB diagram, is probably 'Loco Siding');
2: bank engine(s) that have been waiting on the Old Shed drop down to the Goods Out;
3: when anything on the stops of P4 has removed itself, the bank engine runs through the crossover and settles itself right up against the stops on P4;
4: the through express arrives in P4 from the north;
5: the forward engine(s) is signalled from the Old Shed to P4 as soon as the road can be reset behind the arriving train;
6: the inward engine hooks off, runs forward towards the stops then back through the crossover onto the Goods Out and to the LM/ER shed;
7: the bank engine moves up to the train and prepares for departure.
All this suggests the P4 crossover being fully signalled (shunt signals would be OK) and worked from the box, rather than the kind of GF arrangement used at HH P3.

Of course it needs to be decided whether the bank engine is or is not coupled to the train (a Sectional Appendix entry will need to exist to authorise assistance in rear and coupling or not will be specified there).

Hope that offers something useful again!

Keith
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Re: Port Dinllaen

Unread postby MRFS » Wed May 14, 2014 10:52 am

Cambrian LQs survived until the early 50s at Aberdovey for example.
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Re: Port Dinllaen

Unread postby davidwoodcock » Wed May 14, 2014 1:30 pm

I just wonder whether the historical background might be a little more robust if, instead of the Midland and Great Central getting involved as individual companies, the acquisition had been made through the Cheshire Lines Committee, Britain's biggest joint railway in which the Midland, GC and Great Northern were all equal partners. The facility to export coal from the Nottinghamshire and Yorkshire coalfields directly to Ireland might have been a powerful incentive for all three.

Incidentally, although the Cambrian Railways were grouped into the enlarged GWR in 1923, pre-grouping they had effectively been an associate of the LNWR rather than the GW.
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Re: Port Dinllaen

Unread postby kbarber » Wed May 14, 2014 2:25 pm

davidwoodcock wrote:Incidentally, although the Cambrian Railways were grouped into the enlarged GWR in 1923, pre-grouping they had effectively been an associate of the LNWR rather than the GW.

All the more reason to think they wouldn't have cosied up to the NWIR any more than they had to!
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Re: Port Dinllaen

Unread postby tynewydd » Wed May 14, 2014 4:25 pm

kbarber wrote:Actually I was thinking of 1b as a full-length platform, initially for the GW/Cambrian share of the mail traffic when their station was separate but obviously adding to the flexibility after integration.

Nice but impractical I fear - there just isn't room to extend the platfrom that much in a 21' space with a passageway and a Tan-Y-Graig width before the other wall. I have got juice out of curving the platforms and having them slightly diagonal, but there are limits. However, if we consider that Platform 1b would have been a Victorian creation, coaches (and trains) were considerably shorter. I think the 60s local "sprinter" equivalents for the Canbrian coast could well be short trains, and we also have the possibility of auto-coaches or even early DMUs which get to block the engine release as well...

<snip>

kbarber wrote:Then perhaps the answer is an 'offstage' GW shed

Offstage is actually Pwhelli - a long way and uphill both ways for a turnaround. But - if the turntable could be a 55' just like at Pwhelli (or 9" in OO) then it looks like it would fit if I can exploit the V between branch and main. Big express Castles and so forth would have to slum it with the ER/MR first for turning but all the shorter stuff could do it Swindon fashion! I saw a reference to a 63' Black 5 being turned once at Pwhelli - presumably you have to detach the tender and do it separately and then run around it with the engine. Not sure that is recommended as a standard practice, though. The design of my current MPD has a release line that bypasses the ash/coal and makes directly for the turntable and then there is a line back out again - so that actually makes sense from a "just need turning" POV.

<snip>

kbarber wrote:It sounds as if you're saying double-heading plus a banker as far as T-y-G?

No - technically that would be feasible with DCC - but at the cost of passenger accomodation again. We would end up with 4 coach trains using 2 Pacifics and a banker! I think double heading expresses, banking large passengers/any freight and having short stuff use powerful locomotives would be good. But I'll certainly consider it and your notes on procedure are useful.

kbarber wrote:Of course it needs to be decided whether the bank engine is or is not coupled to the train (a Sectional Appendix entry will need to exist to authorise assistance in rear and coupling or not will be specified there).

If the bankers always run through to TYG - wouldn't coupling be the way to go? Otherwise if the banked train comes to a stand at TYG home - the risk of a rear-end collision exists. If we don't insist on then going to TYG and instead let the banker idle back to PD - the block will be occupied longer I expect - unless the banked section is really short when compared to the block.

kbarber wrote:Hope that offers something useful again!

Keith


Absolutely!

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Re: Port Dinllaen

Unread postby kbarber » Wed May 14, 2014 9:31 pm

Apologies, Adam, for not quite getting how constrained your modelling site is. I realise one of the things you don't have in your pages is a schematic diagram showing the bits you intend to model, the hidden storage and how they all connect up; I wonder if you might be able to put something up (even something rather crude) so we can see what might and what definitely won't work.

So far as the GW shed was concerned I'd imagined locos disappearing into the fiddle yard for turning etc but it sounds as if there's a lot more to it than that. But the more I hear about this scheme, the more I like the concept!

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Re: Port Dinllaen

Unread postby tynewydd » Thu May 15, 2014 10:39 am

Ok - overall (crude as requested) drawing of the scheme - I am trying to tackle each part separately for signaling so we didn't get too distracted. As the center of the scheme PD is first. The 4 stations are actually filled in on the faux history map. I have much more detailed XTRKCAD but hopefully this will give an idea and eliminate clutter.

Not shown - hidden sidings and reversing loop under PD with access to lines to PLJ, TYG and the LMS line to Trefor Junction.

Modeller's license invoked with viaduct along back of PLJ carrying single track from PD to TYG. (Also provides visual break so that PD can't be seen through PLJ).

21'x12' - but the PLJ side is open (there's a garage there) so available as space for operators. Hinged access at Afon Llyni to center operating spaces.

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