Double decker transport - UK compared with Europe

[whole diary]

[NickB]

I write this from the comfort of a train speeding from Brussels to Bruges for the weekend. The train is a double decker similar to other European trains.
I was just wondering, seeing as how the network is full and the platforms too short, as to why we only have single decked carriages?
Thanks

[grahame]

The British system (bridges, tunnels, etc) has a much smaller cross-section so it's quite hard to get a second storey on to a train.   It was tried (somewhat) in South East London with two 4 car units about 60 years ago, with compartments offset above each other - cross seating with (in effect) a compartment above in the luggage racks.  But there were far more seats per door, and station dwell times suffered.

https://www.flickr.com/photos/rw3-497alh/5330944631/

http://en.wikipedia.org/wiki/SR_Class_4DD

[chrisr_75]

I believe the reasons stated by Graham, essentially gauge clearance issues, are, at least in part, a relic of WW2, in that our rail system was relatively lightly damaged (and largely continued to operate "normally") in comparison to that of our continental neighbours, whose rail systems were pretty much rebuilt from scratch post-war. So, we're stuck with Victorian spec railway, whereas France, Belgium, the Netherlands, Germany etc all have mid 20th century specification rail systems that allowed more sustainable growth, particularly with double deck trains & electrification. I understand it is also less of an issue to carry the larger sized shipping containers on Euro rail systems as opposed to ours.

[stuving]

I always through the gauge difference went back to the beginning, and places that got railways even 20-30 years after Britain saw the advantage of bigger loads. According to this that's true for the German sphere of influence, but not the French (perhaps too early). However, they made the effort to upgrade main lines before the WWII^▸ (World War 2 - 1939 to 1945), so post-war reconstruction would not have had much effect  - especially given the small amount of damage in Paris and much of the rest of the country.

I've seen an analysis (no idea where) of the gains from an upstairs, given that it can only fit between bogies and you need stairs. That showed the gain is pretty small, especially for fast-loading commuter trains. That's because moving up and down stairs is slow, so you need more standing space to hold a whole station's joiners and leavers (or to try to). The gain is even smaller for 2-storey RER trains, as they have three doors per carriage, hence three stairways.

[paul7575]

I've seen an analysis (no idea where) of the gains from an upstairs, given that it can only fit between bogies and you need stairs...

You might be thinking of this:

http://webarchive.nationalarchives.gov.uk/20100513020716/http://www.dft.gov.uk/about/strategy/whitepapers/whitepapercm7176/railwhitepapersupportingdocs/provevalddtrains

Basically it isn't just the height of vehicles, the GB^▸ (Great Britain) network usually has less space to deepen carriages between the bogies as well.

Coincidentally the possibility of using double deck trains on discrete parts of the SWML^▸ (South Western Mail Line) (e.g. Waterloo to Basingstoke) has just resurfaced in the Wessex route study draft - though NR^» (Network Rail - home page) still appear lukewarm about it, with only a 50% capacity increase being assumed.

Paul

[4064ReadingAbbey]

Basically it isn't just the height of vehicles, the GB^▸ (Great Britain) network usually has less space to deepen carriages between the bogies as well.

Paul

This is the critical part. British trains evolved with high platforms with the result that the width of the coach below floor level is narrower than the body. In central Europe, and much of France, low level platforms were the order of the day so the coach maintained its width down to rail level.

Although higher platforms are now common in parts of central Europe they are spaced far enough from the rails that there is no interference fit between the train and the platform.

It would be very expensive to enlarge the UK^▸ (United Kingdom) structure gauge on existing lines - not only the platforms would need to be moved but potentially hundreds of under bridges with longitudinal girders between the rails would have to be rebuilt.

[stuving]

Coincidentally the possibility of using double deck trains on discrete parts of the SWML^▸ (South Western Mail Line) (e.g. Waterloo to Basingstoke) has just resurfaced in the Wessex route study draft - though NR^» (Network Rail - home page) still appear lukewarm about it, with only a 50% capacity increase being assumed.
Paul

While there is little detail in the study, it is clear that they are considering clearing a specific route (Waterloo-Basingstoke, and perhaps to Southampton) for these trains which will not (indeed cannot) run anywhere else. That suggests greater height, and/or perhaps greater below-platform width (within the restrictions of third rail stock). They would also only be used for peak service, so potentially one up and one down per day. That, plus being a small-volume custom design, is all going the weight the BCR^▸ (Benefit Cost Ratio) heavily against it.

Interestingly, the 1930s French Voitures ^tage ^tat were also used as peak-busters - though that was not the first double-decker design; that was the Bidel back in 1882 (and very quaint it looks).

[grahame]

Interestingly, the 1930s French Voitures ^tage ^tat were also used as peak-busters - though that was not the first double-decker design; that was the Bidel back in 1882 (and very quaint it looks).

Fascination - From that link, which is in French, via Google Translate:

Bidel is the nickname given to commuter cars to imperial network of former French West . This nickname was given to them because their shape and the barred windows of the upper floor evoked trailers menagerie Bidel of the time. At about the same time, the double-decker open car was put into service from the Gare Saint-Lazare .

These vehicles with two axles and closed imperial included two series:

1882 type 9.5 m in length over buffers, delivered from 1883
1911 type 9.8 m length built from 1911 to 1924.
Built by workshops Romilly-sur-Seine on a lowered chassis Vidard on extremities gooseneck to support pads and hitch, they had a tare weight of 15 t. The ceiling heights were 1.617 m for the lower body (2nd class) and 1.695 m for the Imperial (3rd class).

On 1 January 1938, the park SNCF^▸ (Societe Nationale des Chemins de fer Francais - French National Railways) still included 710 such cars used mainly on the Vincennes line and sometimes on the line Little Belt . The latest units have disappeared from the line Vincennes in 1949; they made ​​their last trip 30 June 1954 on the line of Enghien Montmorency .

[stuving]

Hmm - not one of Google Translate's best - for "network of former French West" read "the old Paris East network" - in fact from the gare de Paris-Bastille to Vincennes. Also, ^ imp^riale ("to imperial", excusably) means double-deck, as applied to buses too (and imp^riale refers to the upper deck itself).

[grahame]

An excellent Pathe Newreel video via
http://www.ianvisits.co.uk/blog/2014/11/22/double-deck-trains-proposed-for-waterloo-station-lines/?

showing how the seating was going to work on the prototype

[grahame]

An old video - introduction of double decker trains from Charing Cross.   I wonder how this will differ from first run of a 387 out of Paddington

https://youtu.be/22GWR3MmBIg

[phile]

Perhaps we won't have double decker trains for fears of bridge strikes where road over rail
 

[simonw]

If the use of rail continues to grow, then someone will have to decide what to do with busy terminal stations, such as those in London.

A typical station with ten platforms, a train turnaround of 2ph (with unloading, cleaning and loading) and 6 primary routes has a limited capacity. With a further growth of 40%(guess) over the next 10-20 years quite likely, are we going to add extra decks of platforms, or deploy double deck trains.

The current Paddington plan of adding two new Crossrail platforms (underground), re-allocate some local platforms to intercity and longer trains makes the current situation more tolerable.

[grahame]

If the use of rail continues to grow, then someone will have to decide what to do with busy terminal stations, such as those in London.

Perhaps someone has ... with Thameslink, Elizabeth Line, Crossrail 2 so far, and HS1^▸ (High Speed line 1 - St Pancras to Channel Tunnel) relieving some pressure inbound from Kent.  Could there be more in the series? 

[stuving]

Perhaps we won't have double decker trains for fears of bridge strikes where road over rail
 

That might be more plausible than perhaps you'd think.

That 2007 Network Rail study into two-storey trains (referred to in this forum before) looked at adapting just one route into London, e.g. Southampton-Waterloo. Just raising the height to French gauge (same width as ours) was costed at the thick end of 1 G£. Doing the same for 16-car trains cost a little less, but gave more extra seats, so would always be a better bet - and you could go on to look at longer trains still.

The real killer for that extra deck is the narrow UK^▸ (United Kingdom) gauge below platform level. Continental gauges go right down at almost the same width, while our trains don't, and can't due to all the stuff down there. The NR^» (Network Rail - home page) study didn't even look at clearing that - dismissed as far too expensive (especially all those bridge girders). If downstairs can only hold 2+1 seating, its benefit is pretty limited.

Raising the height is familiar from electrification, hence much easier to cost. But if you got a few taller trains, you would have to very careful where you drove them. CTRL^▸ (Channel Tunnel Rail Link) and your cleared route (and maybe a short link between) would be OK, but any routeing or signalling brain fade and that hugely embarrassing bridge strike is all too possible.