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Rearward facing frames

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

Re: Rearward facing frames

Unread postby davidwoodcock » Thu Jan 11, 2018 9:26 am

The 1954/5 Southern box at Grain had a rear frame.

I have wondered whether the gradual move to rear frames for mechanical boxes resulted from the increasing use of power frames of one sort or another in signal boxes. I couldn't think of a single "power" box which had a front frame (although doubtless there will now be a long list forthcoming), even the Edwardian LSWR pneumatic boxes (with slides) had rear frames.
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Re: Rearward facing frames

Unread postby Chris Osment » Thu Jan 11, 2018 9:56 am

davidwoodcock wrote:The 1954/5 Southern box at Grain had a rear frame.

I have wondered whether the gradual move to rear frames for mechanical boxes resulted from the increasing use of power frames of one sort or another in signal boxes. I couldn't think of a single "power" box which had a front frame (although doubtless there will now be a long list forthcoming), even the Edwardian LSWR pneumatic boxes (with slides) had rear frames.



....but the two boxes at Salisbury had front frames, as did the one at Grateley IIRC :-)
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Re: Rearward facing frames

Unread postby John Hinson » Thu Jan 11, 2018 10:14 am

I am pretty confident the trand towards rear-mounted frames accompanied the trend of longer lever frames - for reason of view of the controlled layout and access to windows for communication. Some railways. like the GWR and L&NWR, provided access a different way by by leaving spaces for the purpose and making their frames even longer.

However, the earlier mention of the reverse-numbered frame was not at all unique on the LMR - always at shunting frames (at least, those I know of) where there would have been no block shelf or instruments to obstruct the view. And the view was critical as there were rarely any signals or track-circuits. For reasons not established the LMR seem to have designed them and numbered them as if they were rear-mounted frames and it almost looks like a last-minute decision to mount the frame so the operator looks at their layout, but there were so many such shunting frames this does seem unlikely.

And those looking for a consistent policy on the WR might like to consider that the 1963 box at Windsor had a front-mounted frame, a feature retained in 1969 when the structure was re-used at Viaduct Junction.

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Re: Rearward facing frames

Unread postby davidwoodcock » Thu Jan 11, 2018 10:38 am

Chris Osment wrote:
davidwoodcock wrote:......... even the Edwardian LSWR pneumatic boxes (with slides) had rear frames.



....but the two boxes at Salisbury had front frames, as did the one at Grateley IIRC :-)


Which was interesting as I have (in the dim distant past) actually tried pulling and replacing the slides in Salisbury East box and remembered it as a "frame" where one couldn't see the trains when working the slides. The answer, as this photo https://www.pinterest.co.uk/pin/560064903645584042/, shows is that we were both right! It is technically front-framed, the bobby stands facing the trains, but he can't see them until he walks to either end of the (quite long) frame - so perhaps that explains why power frames were subsequently rear facing?
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Re: Rearward facing frames

Unread postby StevieG » Thu Jan 11, 2018 10:43 am

Might one consideration of having front - mounted frames have been if the rules of any companies at one time required signalmen to observe whether their signals responded correctly to lever movements while they were being operated ?
If yes, watching the movement of signals near the box would have been easier from a front - facing frame than while working one at the rear.
...Just a thought.
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Re: Rearward facing frames

Unread postby Danny252 » Thu Jan 11, 2018 11:00 am

John Hinson wrote:And those looking for a consistent policy on the WR might like to consider that the 1963 box at Windsor had a front-mounted frame, a feature retained in 1969 when the structure was re-used at Viaduct Junction.


The only hint of a consistent policy I have found is that the frame arrangement seems to correspond with box design. My suspicion is that there was some argument made that the "traditional" box designs (i.e. not the later flat-roofed designs, and the one-off at Portishead) were not suitable for rear-facing frames for one reason or another. That would at least explain why rear-facing frames appeared as early as 1954, but front-facing ones continued to appear well into the 60s.
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Re: Rearward facing frames

Unread postby Chris Osment » Thu Jan 11, 2018 11:25 am

Certainly by the late 1920s the SR was putting mechanical rear frames in what one might call 'traditional' new boxes, examples including the two boxes at Exeter Central (1925+1927), Ilfracombe (1929), Okehampton (1935) and the 1938 'glasshouse' at Templecombe. But the 1924 Exmouth box had a front frame.
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Re: Rearward facing frames

Unread postby RichardH » Thu Jan 11, 2018 12:03 pm

The LBSCR appears to have standardised on rear frames in the early 1900s, I believe the 3a, and early 3b boxes were front framed, but the 1905 pattern frames seem to have generally been installed at the rear. The 1901 replacement frame at Littlehampton was also installed at the rear, but presumably the original frame was still in situ during the work.

Anything other than rear frames in new SR boxes would have been the exception, but the platform frames were mostly front facing.
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Re: Rearward facing frames

Unread postby jbmack » Thu Jan 11, 2018 4:57 pm

M first box Wilderspool Crossing in Warrington had a rear mounted frame as the box was on girders above the railway.
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Re: Rearward facing frames

Unread postby StevieG » Thu Jan 11, 2018 8:23 pm

FWIW, as Goldsborough's been mentioned, another box which had to my mind, some similarities to it, including flat roof and 'bevelled' corners, was the LNER's c.1945-47, 70-lever Holloway North Down, which replaced a GN box of the same name damaged beyond repair, and the close-by Holloway Carriage Sidings box.

HND arguably had a 'front' frame; - three of its (all Down) running lines being out front (along with a lengthy ladder crossing, jointly-operated with HN Up box, to three Up lines), but also two more running lines 'behind'.
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Re: Rearward facing frames

Unread postby guard_jamie » Fri Jan 12, 2018 12:32 am

Thank you all for the very interesting replies, and apologies for my disappearing from the discussion after setting it rolling - truth be told I only remembered setting it off just now!

The increasing busy-ness of block shelves is a point I had not considered. I hesitate at the assertion that ‘traditional’ boxes were in some way ill-suited to a rearward facing frame, I believe it was a decision more based on sighting and operational convenience.
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Re: Rearward facing frames

Unread postby Andrew Waugh » Fri Jan 12, 2018 9:56 am

The Board of Trade required the signaller to have a good view of the controlled points and signals. As has already been mentioned, the usual reason given for the gradual move towards rear facing frames was that the increasing amount of equipment on the block shelf made it extremely difficult to see out the front windows. But this doesn't explain why some companies adopted rear facing frames and others didn't, as I doubt the equipment on the block shelf varied systematically by company.

I rather suspect that another reason might have been frame design. Most frames were designed with the locking underneath the signaller. This allowed the levers to be placed close to a wall, and the signaller when standing at the frame would be close to the windows.

Some frame designs, however, had the locking behind the levers. I'm thinking particularly of the MR and LMS designs, and also the various direct action tappet frames. As locking got more sophisticated, and typical frames got larger, the locking would have required more space behind the levers. This would have pushed the levers well towards the middle of the box, and meant that the view over the levers would have been limited even with a small block shelf. You certainly couldn't get through the frame to the windows to talk to the drivers.

This would explain why the LMS was such a proponent of rear facing frames, while, say, the GWR wasn't.
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Re: Rearward facing frames

Unread postby John Hinson » Fri Jan 12, 2018 10:10 am

Andrew Waugh wrote:Some frame designs, however, had the locking behind the levers. I'm thinking particularly of the MR and LMS designs, and also the various direct action tappet frames. As locking got more sophisticated, and typical frames got larger, the locking would have required more space behind the levers. This would have pushed the levers well towards the middle of the box, and meant that the view over the levers would have been limited even with a small block shelf. You certainly couldn't get through the frame to the windows to talk to the drivers.

This would explain why the LMS was such a proponent of rear facing frames, while, say, the GWR wasn't.

Alas, that theory doesn't really hold water as the Midland Tumbler frames, almost always mounted in the front of the box, had a massive area of locking behind the levers, but the MR's tappet replacements (mounted in the rear of new boxes) were substantially smaller and the LMS and BR equivalents likewise.

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Re: Rearward facing frames

Unread postby scarpa » Sun Jan 14, 2018 8:01 pm

Banbury North had a front mounted frame until a new longer frame was added in the rear facing position.
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Re: Rearward facing frames

Unread postby Fast Line Floyd » Mon Jan 15, 2018 12:03 pm

Chris Osment wrote:
davidwoodcock wrote:The 1954/5 Southern box at Grain had a rear frame.

I have wondered whether the gradual move to rear frames for mechanical boxes resulted from the increasing use of power frames of one sort or another in signal boxes. I couldn't think of a single "power" box which had a front frame (although doubtless there will now be a long list forthcoming), even the Edwardian LSWR pneumatic boxes (with slides) had rear frames.



....but the two boxes at Salisbury had front frames, as did the one at Grateley IIRC :-)


Feltham Junction Box was an LSW type 4 box with a rear facing Stevens frame.

When Kensington North and South Main got new frames under BR WR the North Box had its new frame (actually second hand) at the front of the box where as the South got its new (really new) frame at the back of the box. The reason for this is that North Main could be closed for an extended period whilst the old frame was removed and the new frame fitted whilst the South could not.
Last edited by Fast Line Floyd on Mon Jan 15, 2018 1:24 pm, edited 1 time in total.
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