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Signal boxes - Great Harwood loop line

British signalling of the past (UK, excepting Northern Ireland)

Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Sat Feb 25, 2017 8:37 am

Hi everyone,

I'm new to this fascinating site, and my interest is in the Great Harwood loop line, a branch line (double line) built by the L & Y railway.

In 1960, there are six signal boxes listed:
Great Harwood junction (Blackburn)
Great Harwood west at one end of Gt. Harwood station
Great Harwood east at the other end of Gt. Harwood station
One at Simonstone station
One at Padiham station
and finally one at Rose Grove (Burnley).

Looking at an old 1912 OS six inch map, it states there are at least two or more signal boxes along the line close to each other, but I don't know if this was a mistake on the map or if these boxes ever existed?

As far as I understand it (and I could easily be wrong), unless needed, the boxes typical spacing was around 3 to 3 and a half miles between each of them?

I know passenger services stopped 1957, and goods 1964, so if these other boxes did exist why would you place them besides the line (which was double track) where there is no sidings, road crossings etc, or was this just a process of running the line down?

Can anyone help with this please.
Thanks, Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby Chris L » Sat Feb 25, 2017 4:29 pm

Hi Andy, welcome to the Forum.

You'll find many details of the various signal boxes on the North Lancashire Loop, including several signal box diagrams, in my book "Signal Boxes on Lancashire & Yorkshire Railway Lines: North-East Lancashire" (details here: https://signalbox.org/books/books2000.htm & here : http://www.hall-royd-junction.co.uk/Hal ... books.html ). I hope you can track down a copy - hopefully your local library should be able to help.

C. 1904 - 1909 the list of boxes on the line was:

Great Harwood Junction
Little Harwood* (closed 1909)
Queen Brick Siding (closed c.1940)
Norden* (2nd box closed c.1919 - 1922)
Great Harwood West
Great Harwood East
Martholme Colliery (closed c.1940)
Simonstone
Padiham Station West [this & next replaced by one box, "Padiham", in 1913]
Padiham Station East
Rose Grove West

(* The original Norden closed and was replaced by another box, also named Norden, located approx. 880 yards to the east, c.1904 - 1907 (details in book). Confusingly both are labelled as SB on the OS map you cite, which also shows Little Harwood SB, although that closed in 1909 [the actual revision date of the 1912 map was 1909]. This might help explain the unusual number of SBs that is puzzling you! Norden was just a "break section" or "intermediate" box, which was only provided to increase capacity on the line, and Little Harwood was only built to ease acceptance problems at Great Harwood Junction, so they didn't have any associated sidings etc.)

Hope that helps!
Chris L.
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Sun Feb 26, 2017 7:47 am

Hi Chris,

Thanks for the warm welcome and the information about the signal boxes, that's great!

The drawing date and release dates being different do make sense with regards to the duplicate signal boxes, it's funny you should mention Norden, I went to the local school there and in 1981/82 went cross country running along the old line.

There were still some mileposts, bits of cable etc still to be found, and the bridges still had signs of soot on them.

I was 18 months - 2 years old (1968) when I saw a steam train go past very close to what was Gt. Harwood station, my granddad lifted me onto a wall, beyond it was a deep cutting. A steam loco went past in the direction of the station pulling some goods.

It seems my granddad and I were one of the last people to see a train on that line - even my granddad said it was strange as the line had long since been closed - that's why i'm interested in this line.

Anyway back to signalling - I've spent a few hours now reading up on the absolute block system on this site, and it really is fascinating. From what you have told me, it seems that signal boxes were added / removed over time depending on the amount of traffic for that line.

Being new to the world of signalling etc, it was something I never thought of!

Just in case anyone is interested, this is what I've found out about the loop line being run down:

The down line (Blackburn to Gt. Harwood - Rose grove) was pulled up between 1966 / 67.
Leaving only the up line - which could be used in both directions as a relief line to the East Lancs line (Blackburn, Accrington, Burnley).

All sidings / relief lines were removed from the up line at the same time as they pulled the down line.

Not sure when the up line was pulled yet, but I know the cutting was filled in, and the top of Unity bridge (Gt. Harwood) just became a strange "hump" in the road.

Thanks,
Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby John Hinson » Sun Feb 26, 2017 9:48 am

andyhunt873 wrote:From what you have told me, it seems that signal boxes were added / removed over time depending on the amount of traffic for that line.

Hi Andy,

That is sometimes the case, but usually the over-riding factor was sidings and yards. Frequency of traffic often didn't demand as many signal boxes as existed, so if the sidings at a particular signal box became disused the box would often be permanenently "switched out" and ultimately abolished.

John
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Sun Feb 26, 2017 10:13 am

John,

Thanks for that.

I've just read about signal boxes being switched out, so I understand what you mean by that.

When a signalman pulled a lever at his box (say to set a signal or point), was it just purely a mechanical connection from the box to the signal / point - if so, it must have taken some pulling - is this the reason why unless needed in between, boxes where around 3 miles apart? or was that a typical length of block track where no sidings / crossings etc existed?

Obviously electric was used for the block instruments (indicators / bells) at each box, and I read there were indicators for things like the distant signals showing on? presumably because many signals could be a long way away from the box or out of sight?

Thanks,
Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby S&TEngineer » Sun Feb 26, 2017 10:36 am

Hi Andy and welcolme to the forum. We have lots of expertise on here and are are always happy to help newcommers with what can turn out to be a very complex subject when you start to delve into it in some depth (I've been involved in it professionally since I left school nearly 50 years ago, and I still learn something new each day). May I suggest you start with having a read of the subjects covered under Levers No.2 and 3 at the top of the main Signalbox Website here: https://signalbox.org/index.php
Regards,
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Re: Signal boxes - Great Harwood loop line

Unread postby John Hinson » Sun Feb 26, 2017 10:43 am

andyhunt873 wrote:When a signalman pulled a lever at his box (say to set a signal or point), was it just purely a mechanical connection from the box to the signal / point - if so, it must have taken some pulling - is this the reason why unless needed in between, boxes where around 3 miles apart? or was that a typical length of block track where no sidings / crossings etc existed?

It is difficult to generalise but boxes were usually positioned where they were for the following reasons:
  • Stations
  • Junctions
  • Sidings
  • Level Crossings
So there was no need to really think about spacing when they were being constructed, although on very busy main lines where the odd box would later be placed between the above to increase capacity. Such efforts were often wasted and followed closely by four-tracking as a better solution.

There were limits on the distance mechanical points were permitted from the box, which varied over the years but was typically 350 yards meaning a box could work 700 yards of layout. There was no specific limit on distance to signals but of course their positioning related to the pointwork.

John
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Sun Feb 26, 2017 11:33 am

John & S&TEngineer,

This is really fascinating stuff to me, seems (and obviously) they were mechanically operated for many years, then new technology was tried out (combination of mechanical / pneumatic / electrical) over time.

The interlocking mechanism preventing signals from being "off" by mistake to me looks a little like you have when you place a key in a lock, only when all are turned (or in this case free) can the lever be pulled.

So, if I've got this right, in order to set a signal to "off", if required, certain points would have to be set accordingly and in turn "free" a (what I call a latch) out of the way. Once this had been done (and all the "latches" are clear) the lever for the signal could be pulled to "off?

I was watching BBC Keeping Britain on track - west cost episode last night, there was an interview with a signalman at Blea moor box (Settle - Carlise line), and thanks to this site I was able to understand part of the interview.

The bell rang at his box 3-1-1 (Is line clear for freight), and he answered 4-3 (Line clear to home signal).

Seen that episode before, but always wandered what the conversation was!

Thanks again,
Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby Chris L » Sun Feb 26, 2017 4:26 pm

Perhaps a few more sentences about Little Harwood signal box would be interesting here, whilst discussing Absolute Block principles.

When the final box at Great Harwood Junction was opened in 1898, it was not initially equipped with an Up Branch Outer Home signal. As the Up Branch Home was less than 440 yds from the junction itself (i.e. the junction was within the "clearing point"), this meant that, according to Absolute Block Regulation 4, the route through the junction would have to be set and maintained for any train approaching from the branch before it could be accepted.

An Outer Home (at a distance of 440 yds or more from the Inner Home) was not initially provided because it (and any train standing at it) would have been well out of the sight etc. of the Signalman. Track Circuits were not, in 1898, yet in common use in the UK.

Because at certain times this situation would create delays for trains on the main lines, an extra signal box was opened at Little Harwood on 22.3.1899, approx. 870 yards from Great Harwood Junction box, along the branch; this meant that by the time Little Harwood offered an Up train to Great Harwood Junction it would be a lot closer than otherwise, and therefore the amount of time Great Harwood Junction's junction would have to be set for its approach would be significantly less.

In 1909, however, an Up Branch Outer Home signal - together with an associated Track Circuit - was provided at Great Harwood Junction; thus the purpose of Little Harwood box disappeared and it closed, because now Great Harwood Junction could accept a train on the Up Branch under reg.4 without having to set the junction for it immediately.

In this case (as so often in later signalling history!), therefore, the reason for Little Harwood signal box's demise was not lessening of traffic, but technological advance!

Chris.
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Mon Feb 27, 2017 12:17 pm

Chris,

Thanks again for more information regarding the little harwood box.

I've had a good read about track circuits for a block system, and saw diagrams showing how, when a train enters a block the signal guarding the block (to the rear of the train) turns red. But it then (on this example) shows green again when the train has left the block section for the next one.

Now on the manual systems, (if I've got this right) Once a train enters the block, the signal to the rear of the block is set to on (danger) to stop another train entering the block, and so on down the line.

So if there was only one train for an hour, and the journey took 25 minutes, by the time it arrived at it's destination all the stop signals along that line behind it would now be at stop.

So the "normal" state of the stop signals are at stop (danger), but on the example track circuit diagrams, when the train leaves it's block (i.e. moves to the next block), the signal guarding the first block is set to green again.

This seems to contradict the manual system? did I miss something?, or was this (as I suspect) just a simplified example?

Confused (but it's me of course).

Thanks,
Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby Mike Hodgson » Mon Feb 27, 2017 6:06 pm

Under Absolute Block (the traditional mechanical system) the normal aspects shown by signals was danger/caution and they were only moved to clear shortly before the passage of a train. This was done manually by a signalman pulling/releasing a lever.

The more modern system with colour lights is generally worked under Track Circuit Block (different set of regulations), and the signals on plain track would normally be worked automatically, so they show clear when there are no trains about. They automatically go to Danger when necessary to protect a train from another which might be following, but only for so long as the relevant track circuit remains occupied. The signalman might be provided with a switch so that such signals can be put to danger in emergency, but in normal operation signals are left to work automatically. This is not good enough at junctions however, so signals there are controlled by a signalman and he would normally still leave them set to Danger until necessary to clear them for a train.

The above is a gross over-simplification, but it gives you some rules of thumb.
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Re: Signal boxes - Great Harwood loop line

Unread postby Chris L » Mon Feb 27, 2017 6:14 pm

Hi again Andy,

I think you are confusing the use of Track Circuits where "Absolute Block" regulations apply (the "old manual" method of signalling), with their use where the very different "Track Circuit Block" regulations are in force.

Have a look at these two webpages, which might help to start to explain the differences;-
http://www.railsigns.uk/info/ablock1/ablock1.html
http://www.railsigns.uk/info/tcb1/tcb1.html

What I described at Great Harwood Junction falls very firmly into "Absolute Block" territory!

Chris.

Edit - Ha! - Mike beat me to it while my response was still being composed!
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Tue Feb 28, 2017 1:06 pm

Mike & Chris,

Thanks to both of you, yes I was getting confused between the two, with explanations from you both, and more reading (via the links), I understand a lot more now, and it's clearer!

I read somewhere recently that (on the subject of signalling), you either get drawn into it, or you stay clear, I have to say I'm enjoying signalling.

For most of my life, I've enjoyed visiting preserved locos / lines, but never really thought too much on how the actual lines were run, (e.g. signalling / keeping trains apart etc).

So thanks to everyone here, this has opened a whole new world of the railways to me!

Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby andyhunt873 » Thu Mar 2, 2017 1:40 pm

Hi everyone,

I know this is not really concerned with signalling, but I thought someone might be able to help.

My friend Bernard wants to give a talk about people using the trains during "wakes weeks" and going to Blackpool for their holidays.

Has anyone got / know of copyright free photos that Bernard could use during his talk / or with your permission?

Just thought I'd ask, as you've all been very helpful to me.

Thanks,
Andy.
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Re: Signal boxes - Great Harwood loop line

Unread postby Stuart Johnson » Mon Mar 6, 2017 1:15 pm

Question about control of block section moved to new thread
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