Suicide Pit Depth

[spsmiler]

I was wondering about the depth of suicide pits at deep level tube stations - the reason is for railway modelling purposes.


I searched through existing messages here at DD and whilst I did find a thread from 2005 which was about these pits it did not reveal the information I seek. This thread is here: districtdavesforum.co.uk/thread/215/pits

From other threads which my search found it seems that the pits varied in depth. My thoughts (based on guesswork and observation of photos and the real thing) are that the pits will be circa 3ft to 4ft deep, which in OO scale would be between 12 mm and 16 mm.

Simon

[jimbo]

I seem to recall that some stations on the Picc extension were provided with a pit of two depths, so that it was easier to walk along under a train to one side of the current rail to reach the problem area.

[spsmiler]

jimbo I hardly ever go that way, so have no idea about that.

I should have also asked yesterday about dimensions - I'd guess that each riser that form the piers are about 3 inches* by 2 inches (width / depth) and the full pier is the same length as a wood sleeper width.

*about the same width as the tube tunnel sized conductor rails

The total height of the pier plus insulator pot is the big question mark - depending on the depth of the pit.

For modelling purposes what also matters is the choice of track. I have both Peco code 100 and code 70 tracks, both with plastic imitation wooden sleepers. The code 70 tracks seem flimsier whereas the code 100 has a larger cross-section and seems is sturdier.

For modelling purposes my thoughts are that 1mm square plastic strip is the closest visual match to tube tunnel conductor rails. Of course it will need painting, erm gun metal looks about right. I might however go for live centre rail (for the internal lighting) using Marklin power collection shoes - if they will fit under the bogies! Why? Then I can have the lights go off at pointwork!

[brigham]

You can represent the flashing with an LED, too!

[spsmiler]

Jun 7, 2022 16:40:52 GMT brigham said:

You can represent the flashing with an LED, too!

That is something different - I feel sure that there is a company which sells a kit to replicate this.

I was thinking of the gaps in the power rails at pointwork which frequently used to result in most of the lights going out for a few moments as different parts of the train travelled over the points  

[xtmw]

Jun 7, 2022 12:12:24 GMT spsmiler said:

jimbo I hardly ever go that way, so have no idea about that.

I should have also asked yesterday about dimensions - I'd guess that each riser that form the piers are about 3 inches* by 2 inches (width / depth) and the full pier is the same length as a wood sleeper width.

*about the same width as the tube tunnel sized conductor rails

The total height of the pier plus insulator pot is the big question mark - depending on the depth of the pit.

For modelling purposes what also matters is the choice of track. I have both Peco code 100 and code 70 tracks, both with plastic imitation wooden sleepers. The code 70 tracks seem flimsier whereas the code 100 has a larger cross-section and seems is sturdier.

For modelling purposes my thoughts are that 1mm square plastic strip is the closest visual match to tube tunnel conductor rails. Of course it will need painting, erm gun metal looks about right. I might however go for live centre rail (for the internal lighting) using Marklin power collection shoes - if they will fit under the bogies! Why? Then I can have the lights go off at pointwork!

It's amazing to see bullhead rail still being used!!

[jimbo]

Before low-voltage circuits there was no emergency lighting, so if a train came to a stand over a current rail gap, we all sat there quietly in the total dark! I recall Q stock and standard tube stock in the 1960s.

[aslefshrugged]

I think you'll find the pits are there for drainage

[spsmiler]

Jun 7, 2022 19:24:35 GMT xtmw said:

Jun 7, 2022 12:12:24 GMT spsmiler said:

jimbo I hardly ever go that way, so have no idea about that.

I should have also asked yesterday about dimensions - I'd guess that each riser that form the piers are about 3 inches* by 2 inches (width / depth) and the full pier is the same length as a wood sleeper width.

*about the same width as the tube tunnel sized conductor rails

The total height of the pier plus insulator pot is the big question mark - depending on the depth of the pit.

For modelling purposes what also matters is the choice of track. I have both Peco code 100 and code 70 tracks, both with plastic imitation wooden sleepers. The code 70 tracks seem flimsier whereas the code 100 has a larger cross-section and seems is sturdier.

For modelling purposes my thoughts are that 1mm square plastic strip is the closest visual match to tube tunnel conductor rails. Of course it will need painting, erm gun metal looks about right. I might however go for live centre rail (for the internal lighting) using Marklin power collection shoes - if they will fit under the bogies! Why? Then I can have the lights go off at pointwork!

It's amazing to see bullhead rail still being used!!

The photo is not new - dates from circa 2005 / 2006.

[Tom]

The pits on the early tube lines aren’t that deep, maybe 18 inches or so. I’ll check next time I get the chance.

On the Victoria line they are much deeper, and as jimbo says, they’re two depths. The shallow side, furthest from the platform, is around 3 feet, and the deeper side is over five feet - from memory around 5’ 8”.

I’ll see if I can find some drawings with the dimensions.

[spsmiler]

Jun 7, 2022 23:02:34 GMT Tom said:

The pits on the early tube lines aren’t that deep, maybe 18 inches or so. I’ll check next time I get the chance.

On the Victoria line they are much deeper, and as jimbo says, they’re two depths. The shallow side, furthest from the platform, is around 3 feet, and the deeper side is over five feet - from memory around 5’ 8”.

I’ll see if I can find some drawings with the dimensions.

Thanks

The ones at the new stations in the Northern line extension to Battersea seem quite shallow. But 18" sounds so little that even if laying down a person (especially a large adult) might still be struck by a train, especially if they have a back pack.

[towerman]

Jun 7, 2022 23:02:34 GMT Tom said:

The pits on the early tube lines aren’t that deep, maybe 18 inches or so. I’ll check next time I get the chance.

On the Victoria line they are much deeper, and as jimbo says, they’re two depths. The shallow side, furthest from the platform, is around 3 feet, and the deeper side is over five feet - from memory around 5’ 8”.

I’ll see if I can find some drawings with the dimensions.

A average sized person can walk under a train crouched down in Vic Line suicide pits.Know this as I checked a train for badly flatted wheels at Finsbury Pk SB back in the early 70s.

[spsmiler]

I've worked out some dimensions, but most likely they will need changing...

For reasons that I'm sure everyone can fully understand, I have never actually been close enough to measure the piers that support the conductor rail. From looking at them I'd guess that each of the two risers that forms the main part of the piers is (width / depth) about 4 inches (100 mm) by 2 inches (50 mm) and the full pier length is about the same length as the width of a wood sleeper - approximately 10 inches (255 mm).

As the depth of the anti-suicide pits is not consistent throughout the London Underground network so the total height of the piers (including insulator pots) also varies according to location.

My first thought was that the model railway versions need to be 16mm high.

This is based on the pits being 3 foot deep, which works out at 12 mm in OO scale; with the sleepers and tracks adding another 4 mm (I will be using Peco code 100 rail, which is 4 mm high).

But I am now thinking that 16 mm will look wrong - too tall - so if I assume the pits are 2' 6" deep I could reduce their height by 2 mm. For 2 foot pit depth I can reduce the height by another 2 mm - to 12 mm. If just 18 inches then the piers should be just 10 mm high. My photos from the two Northern line stations which opened in September 2021 (Nine Elms and Battersea Power Station) show the section of the pier which is in two sections (two smaller piers) is 'less high' than seen in my photograph on this page. 

I am not keen on using Peco code 70 rail but if I did it would reduce the support piers height a little more.

The top of the centre conductor rails are actually 1½" (38 mm) above the running rails and to represent the conductor rails I've already suggested that I will be using evergreen 1 mm square strips, as it seems to be the closest format to the type of conductor rail used in deep level tube train tunnels. To get an even better match for 'the real thing' I probably should add a strip (perhaps 0.25 mm thick and 0.85 mm high) along each side of the conductor rail. But would anyone actually see this?


Next I need to think of the live rail.


btw: research looking through my 'digital camera images' folders on my computer shows that the photo showing the pit came from Gants Hill, so the pit would have been built as part of the original design - not added later as in central London. I can also confirm that the photo was taken in December 2004. As for the choice of rail types (flat bottom or bullhead) a photo that I took last month (May 2022) shows that the tracks through this station still comprise bullhead rail. 

[jimbo]

Jun 7, 2022 20:20:38 GMT jimbo said:

Before low-voltage circuits there was no emergency lighting, so if a train came to a stand over a current rail gap, we all sat there quietly in the total dark! I recall Q stock and standard tube stock in the 1960s.

Thought I should mention, if the whole job shut down, the guard would walk through with his oil lantern and light the emergency candle in each car. He was issued with a monthly box of matches for these purposes. Emergency candles were even provided in 1967 tube stock on the Victoria Line since batteries were not proven to last two hours for passenger evacuation. If current was discharged, tunnel emergency lighting would come on, but there was only the occasional incandescent globe since many were missing or broken. There was often some lighting provided around track points to help station staff required to secure them in case of failure. After dark in the open there could be no other light. Trains also used oil tail lights until electric tail lights became more reliable. Sorry for the diversion! Hope this is of interest.

[Tom]

Jun 7, 2022 23:02:34 GMT Tom said:

I’ll see if I can find some drawings with the dimensions.

I've now got them:
The deep side is 1500mm deep (below nominal rail level) x 460mm wide, the shallow side is 760mm deep x 740mm wide.

Conductor rail pedestals are at 2745mm intervals.

[stapler]

Apropos of nothing, the man who initiated/installed the suicide pits was Vernon A M Robertson, LT Chief engineer in the 30s, and a distinguished engineer nationally, who was president of the Institute. Oddly enough, his name came up on Wednesday at the Epping Forest planning committee, in discussion of an application to demolish his former house in Buckhurst Hill...
Appreciate this won't help railway modellers!

[rheostar]

A friend took a picture of Finsbury Park pit. You can just about see the deeper section on the right hand side.

Finsbury Park pit by rheostar, on Flickr

[brigham]

The notion of these being 'anti-suicide pits' seems to stem from no less an authority than H G Follenfant, one-time Chief Civil Engineer of LT, whose transport career started in 1929 with London Electric Railways.

He writes: "In the late 'twenties, it became apparent that serious consideration would have to be given to the re-design of the platform tracks as there was a growing tendency for people determined on suicide to adopt the positive method of jumping in front of approaching trains - a most inefficient method and more likely to cause serious injury than quick death. The unpleasant task of removing the injured person from under a tube train on cross sleeper track in a platform ground at tube clearances was both lengthy and difficult, causing serious interruption to train services. It was also thought that the sight of a pit might persuade the intended suicide to go elsewhere."