(Trivia?) Multiple Unit doors

[southern442]

Are there any diesel or electric multiple units that feature sliding/plug doors that don't bend inward at the bottom? The only ones I can think of are the ex-LU ones (483's, 230's etc). Is there any particular reason why sliding doors bend inwards at the bottom?

 

[superalbs]

Probably because the whole body of the train also bends inwards. :P

 

[30907]

Off the top of my head, they follow the vehicle profile which itself is constrained by the loading gauge. For whatever reason, LUL stock doesn't generally bulge at the waist (is this because filling a tube tunnel to the maximum simply creates aerodynamic problems?).

There is plenty of stock in mainland Europe that is pretty much slab sided, there being little to be gained by curving the sides. Offhand the major exception is the German ICE.

 

[JN114]

Pacers?

 

[southern442]

Pacers?

I guess they could count, although their doors are in-folding rather than sliding, so a bend at the bottom would potentially make things a bit awkward.

 

[Clansman]

Newcastle Metro rolling stock doesn't bend suddenly at the bottom.

 

[southern442]

Probably because the whole body of the train also bends inwards. :P

I suppose it would have also been worth me mentioning that Although some units (particularly those with sliding and plug doors) bend inwards much more noticeably than others. For example, there is a visible inward curve on electrostars and turbostars, compared to pacers which hardly have a bend at all (there is one there, but it's very small and sharp and the doors don't curve inward and probably wouldn't even if they were sliding)

 

[D365]

I'm fairly sure that the PEP/Mk3-based stocks (Class 442 excluded?) use sliding doors that are not curved in any way.

EDIT: Never mind then

 

[Clansman]

I'm fairly sure that the PEP/Mk3-based stocks (Class 442 excluded?) use sliding doors that are not curved in any way.

They are slightly curved at the bottom.

 

[superalbs]

They are slightly curved at the bottom.

That looks like a Class 318 judging by the size and shape of that window.

 

[hurricanemk1c]

LHB DART sets don't curve I believe

 

[Carntyne]

That looks like a Class 318 judging by the size and shape of that window.

It's a 318 in the photo but 314/320 do curve at the bottom too, had a look this morning.

 

[Great_Western]

Would those Class 139's count?

 

[theageofthetra]

The old District/Circle line stock. Also wasn't there an experimental unit in the 30's which splayed out at the bottom?

 

[causton]

I'm fairly sure that the PEP/Mk3-based stocks (Class 442 excluded?) use sliding doors that are not curved in any way.

EDIT: Never mind then

I was convinced as well!

But...

http://www.networksoutheast.net/uploads/3/5/5/9/3559064/1542468_orig.jpg?458

Bah!!

 

[SpacePhoenix]

The units on the DLR have straight doors.

 

[superalbs]

Also wasn't there an experimental unit in the 30's which splayed out at the bottom?

https://upload.wikimedia.org/wikipe...painted_and_unpainted_at_South_Kensington.jpg

That'd be the LU R Stock. Also had weird windows sticking out as well, quite a weird one that.

 

[Deepgreen]

The 'tumble-home' (the term for the inward curving profile) dates from the BR mk2 stock in the 60s. Sliding doors stocks from that time have almost all included the profile in their design. The London Transport 'R' (silver/white) and 'CO/CP' (red) stock (precursors to the D78 and C stocks) had flared sides and doors. Their hopper (lift handle and pull) windows were enclosed in lozenge-shaped fairings.

 

[edwin_m]

Mk1 stock did have a slight tumblehome but far more gentle than later stock and starting higher up.

The Underground (sub-surface) structure gauge is slightly wider near platform level so classic sub-surface stock can be flat-sided. The outward taper on CO, CP and R stock is effectively the same profile as the door steps and might save someone at the edge of a platform from being struck by the edge of a step on a moving train. The class 230 conversion had to have its body raised slightly so the area around the door steps would be in gauge for Network Rail. However S stock does taper inwards and I think this is because the floor is lower.

One way the UK structure gauge is unusual is that it is much narrower below platform level than higher up. Most other railways have the same width nearly down to rail level so their trains can have flat sides and doors.

 

[Wivenswold]

The original idea for the flared skirts on the CO/CP & R stocks was to stop people trying to ride on the outside of the trains. But the design proved problematic as doors would stick when the train was loaded due to the chassis buckling under the weight.

Lovely old trains, real art-deco design and never bettered in my opinion. It's a scandal that a full train wasn't kept for special events but money was tight back in the early 80's.

Friends of the London Transport Museum are slowly trying to get a working model back in to service using a mixture of Q stock cars that remain. Though there have been few updates since I heard that C-Stock compressors had been saved for the project in 2014.

 

[southern442]

Would those Class 139's count?

The 139's don't have sliding doors so technically they don't count, however they are interesting and relevant to the discussion as they don't appear to bend inward at all at the bottom of the main body, although they are quite narrow so there probably isn't a need to.

Also, I've realised that another exception to the rule is the class 374, which don't have the inward bend on their doors at all. In fact, they are rather like tube doors, with a large bend at the top

 

[142094]

Newcastle Metro rolling stock doesn't bend suddenly at the bottom.

There is a slight bend near the middle, although if you are not looking for it you wouldn't notice it.

 

[E_Reeves]

Class 230?

 

[43021HST]

The 'tumble-home' (the term for the inward curving profile) dates from the BR mk2 stock in the 60s. Sliding doors stocks from that time have almost all included the profile in their design. The London Transport 'R' (silver/white) and 'CO/CP' (red) stock (precursors to the D78 and C stocks) had flared sides and doors. Their hopper (lift handle and pull) windows were enclosed in lozenge-shaped fairings.

Might I suggest that a lot of prenationalisation stock had a 'tumble home'

Much of the post war Bulleid EMUs had such a severe tumblehome, it gave them a rather distinctive outline, with the exception of the 4DD units.

 

[Deepgreen]

The original idea for the flared skirts on the CO/CP & R stocks was to stop people trying to ride on the outside of the trains. But the design proved problematic as doors would stick when the train was loaded due to the chassis buckling under the weight.

Lovely old trains, real art-deco design and never bettered in my opinion. It's a scandal that a full train wasn't kept for special events but money was tight back in the early 80's.

Friends of the London Transport Museum are slowly trying to get a working model back in to service using a mixture of Q stock cars that remain. Though there have been few updates since I heard that C-Stock compressors had been saved for the project in 2014.

Well, in 37 years on the Underground I've never heard that explanation before! At least 'tagging' wasn't big in the 1940s!

 

[Deepgreen]

Might I suggest that a lot of prenationalisation stock had a 'tumble home'

Much of the post war Bulleid EMUs had such a severe tumblehome, it gave them a rather distinctive outline, with the exception of the 4DD units.

Quite so - my allusion to Mk2 stock was only because their profile adopted the now-familiar uniform curved shape rather than the various multi-radius 'tumble-homes' previously used. In fact, most stock had curved profiles except where route requirements precluded it - Hastings, etc. The 4DDs were unusual (unique?) on BR in having slab sides despite being built specifically for a route with a 'normal' loading gauge (obviously because their design required maximum use of the space available). As an aside, I remember my only trip on them, when my father took us for a ride shortly before their withdrawal. It was a very hot summer's day (August 1971, I think; London Bridge to ?) and the upstairs area was sweltering - the upper windows were fixed to avoid head/bridge interaction!