Could Double Deck trains be viable in the UK?

[Teflon Lettuce]

Not sure if I've started this thread in the right place but here goes:-

What exactly is it that stops trains from being double deck in the UK?

Are the bridges really too low for even "lowbridge" designs of DD carriages? or is it, like bendybuses, UK resistance to "strange foreign ideas"?

 

[Bletchleyite]

It's a combination of a few things.

Typically the loading gauge is quite low. But also it's quite narrow below platform level and higher up. So what you'd get is a very narrow 2+1 both upstairs and downstairs, but then a stack of wasted space on wider doors and stairways (if you look at a German double decker the double deck saloons only run about 2/3 of the length, while the Swiss ones manage a full length upper saloon but a very short lower one which is only about half the length).

Or, instead, you could have a full width and full length (barring two sets of doors) with 3+2 seating, and get more seats in with easier access and a higher level of comfort (yes, really).

It was tried once - the 4-DD unit, but didn't work too well.

 

[4141]

Search for "double deck" on this site, there have been a few threads over the years...

 

[Teflon Lettuce]

It's a combination of a few things.

Typically the loading gauge is quite low. But also it's quite narrow below platform level and higher up. So what you'd get is a very narrow 2+1 both upstairs and downstairs, but then a stack of wasted space on wider doors and stairways.

Or, instead, you could have a full width and full length (barring two sets of doors) with 3+2 seating, and get more seats in with easier access and a higher level of comfort (yes, really).

It was tried once - the 4-DD unit, but didn't work too well.

I'm not sure what you mean narrow below platform level... do you mean the shape of the actual carriage? if so surely that can just be addressed by coming up with a squarer design?

 

[Teflon Lettuce]

Search for "double deck" on this site, there have been a few threads over the years...

ok will do

 

[Bletchleyite]

I'm not sure what you mean narrow below platform level... do you mean the shape of the actual carriage? if so surely that can just be addressed by coming up with a squarer design?

No, the amount of space available for the coach.

Compare UIC loading gauges:

with British ones (W6 is the usual):

...and how narrow it gets below platform level? I dont think that diagram is properly to scale, the "cut in" is much more pronounced than it seems to show.

You could go for a 2500mm wide body, but you aren't going to get very comfortable seating in it. Even the 23m Desiros feel very narrow, and those are 2673mm.

You've also only got about 3500mm of height to play with inside your theoretical DD coach, which is going to result in *very* low ceilings, slowing down passenger movement substantially.

 

[Bletchleyite]

To put the 3965mm overall height from rail level into perspective, it appears a Bristol Lodekka is 13ft 6in high, or about 4115mm. And that is vertically quite cramped.

 

[hwl]

I'm not sure what you mean narrow below platform level... do you mean the shape of the actual carriage? if so surely that can just be addressed by coming up with a squarer design?

There are quite a number of narrow width under bridge girders that limit width below platform height in the UK compared to the continent

 

[swt_passenger]

Not sure if I've started this thread in the right place but here goes:-

What exactly is it that stops trains from being double deck in the UK?

Are the bridges really too low for even "lowbridge" designs of DD carriages? or is it, like bendybuses, UK resistance to "strange foreign ideas"?

Here’s the most recent thread I found. Only June, but there are quite a few more:
https://www.railforums.co.uk/threads/double-deck-trains.151344/

I usually provide a link to the DfT report on the subject:
http://webarchive.nationalarchives....whitepapersupportingdocs/provevalddtrains.pdf
There are detailed explanations of the lower structure gauge problems in there, it certainly isn’t just platforms.

In the executive summary (page 6) they emphasise the fairly minimal capacity gains for possible GB gauge 20m vehicles, and the slightly higher increase available for 23m vehicles, and that running 16 x 20m trains rather than 12 x 20m actually gives a higher benefit.

 

[Teflon Lettuce]

There are quite a number of narrow width under bridge girders that limit width below platform height in the UK compared to the continent

ok so that begs the question why, when we are in desperate need of extra capacity on the railway and we are spending billions on upgrades, don't network rail spend the extra removing the obstacles that stop DD operation? After all, even if you only have 13' 6 clearance then, between the bogies you could sling the lower deck to within a ft of the ground {there aren't any speed humps on the railways are there?} leaving 12' 6 headroom to share between the 2 decks.. even taking 6" for the upper deck floor that still leaves 6' headheight for each deck... now I don't know about anyone else... but if I was commuting every day an hr each way I'd prefer a seat with a lower ceiling rather than stand crushed next to a bunch of strangers safe in the knowledge that there's 4' of wasted space above my head...

 

[hwl]

ok so that begs the question why, when we are in desperate need of extra capacity on the railway and we are spending billions on upgrades, don't network rail spend the extra removing the obstacles that stop DD operation? After all, even if you only have 13' 6 clearance then, between the bogies you could sling the lower deck to within a ft of the ground {there aren't any speed humps on the railways are there?} leaving 12' 6 headroom to share between the 2 decks.. even taking 6" for the upper deck floor that still leaves 6' headheight for each deck... now I don't know about anyone else... but if I was commuting every day an hr each way I'd prefer a seat with a lower ceiling rather than stand crushed next to a bunch of strangers safe in the knowledge that there's 4' of wasted space above my head...

DD loading and dwell times are bad.
Lots of bridges and tunnels would need sorting too.

 

[Teflon Lettuce]

DD loading and dwell times are bad.
Lots of bridges and tunnels would need sorting too.

in my experience with buses stop dwell times per passenger are no better or worse for dd's than sd's and I'm sure that with one way flow through carriages that could, by and large be mitigated completely.

As to the amount of work needed.. I'm not advocating the WHOLE of the network being upgraded for DD's, but surely there's a route or 3 that are seriously overcrowded that could be converted to DD with minimal extra cost?

 

[swt_passenger]

ok so that begs the question why, when we are in desperate need of extra capacity on the railway and we are spending billions on upgrades, don't network rail spend the extra removing the obstacles that stop DD operation? After all, even if you only have 13' 6 clearance then, between the bogies you could sling the lower deck to within a ft of the ground {there aren't any speed humps on the railways are there?} leaving 12' 6 headroom to share between the 2 decks.. even taking 6" for the upper deck floor that still leaves 6' headheight for each deck... now I don't know about anyone else... but if I was commuting every day an hr each way I'd prefer a seat with a lower ceiling rather than stand crushed next to a bunch of strangers safe in the knowledge that there's 4' of wasted space above my head...

The report I linked to explains the costs for some typical busy routes. In the order of £1bn for one route, such as London to Brighton. It would be off the scale to be done in multiple areas. And that’s a report done over ten years ago.

 

[Teflon Lettuce]

The report I linked to explains the costs for some typical busy routes. In the order of £1bn for one route, such as London to Brighton. It would be off the scale to be done in multiple areas.

ok £1bn for London to Brighton.... and how much in total has been spent upgrading that route in the last 10 yrs?

or to put it another way... how much is Crossrail costing? and how much extra would it have cost to make it capable of DD operation?

 

[Bletchleyite]

or to put it another way... how much is Crossrail costing? and how much extra would it have cost to make it capable of DD operation?

Crossrail would have been a lot cheaper to do than most other established UK lines largely because most of it is new build or at least new electrification (and the GWR has quite a large loading gauge anyway). I must admit to being surprised that it was not built to UIC gauge double deck.

 

[swt_passenger]

Crossrail would have been a lot cheaper to do than most other established UK lines largely because most of it is new build or at least new electrification (and the GWR has quite a large loading gauge anyway). I must admit to being surprised that it was not built to UIC gauge double deck.

The tunnels would accept a double deck train. The existing surface sections wouldn’t, but more especially Heathrow tunnel wouldn’t. This has been discussed before, DfT had said in an FOI reply that platforms and OH would need altering but UIC gauge GB trains would then fit.

 

[Bald Rick]

ok £1bn for London to Brighton.... and how much in total has been spent upgrading that route in the last 10 yrs?

How much hasn’t been spent ‘upgrading’ the Brighton Main Line for higher capacity in the last 10 years? Not very much at all. New platforms at Gatwick and Redhill, that’s your lot.

 

[Teflon Lettuce]

How much hasn’t been spent ‘upgrading’ the Brighton Main Line for higher capacity in the last 10 years? Not very much at all. New platforms at Gatwick and Redhill, that’s your lot.

odd it appears to be a regular for total blockades for engineering..I assumed it was for upgrade

 

[Bald Rick]

odd it appears to be a regular for total blockades for engineering..I assumed it was for upgrade

That’s renewals. No upgrade in capacity or capability.

 

[alangla]

Crossrail would have been a lot cheaper to do than most other established UK lines largely because most of it is new build or at least new electrification (and the GWR has quite a large loading gauge anyway). I must admit to being surprised that it was not built to UIC gauge double deck.

I can't help feeling that Crossrail, as new build, was an opportunity missed.

On the question of boarding times, the last time I was in Sydney (a while ago now), I don't remember their all double deck suburban fleet being slow loading. They did, however, have huge double end doors and a large single deck standing / circulation / disabled & pram space around the doors

 

[4-SUB 4732]

The key issue for the Bulleid Double Decker is that it wasn’t really double deck. It was a shocking example of design.

Look at German S Bahn / Regional Stock and it is a model of efficiency in people movement. Doors are approaching 2 metre wide allowing up to 4 people to disgorge at once and a big circulating space let’s people in quickly.

We should, realistically, have sought to provide passive provision for Double Deck as part of a number of routes we were electrifying.

Imagine how marvellous it would have been to have Double Deck stock operating on the Great Eastern... It might still be the answer to their prayers!

 

[AM9]

... Imagine how marvellous it would have been to have Double Deck stock operating on the Great Eastern... It might still be the answer to their prayers!View attachment 52154

I doubt it. The GEML certainly has capacity issues but double deck trains would have ridiculous infrastructure cost implications to even consider it as an option. FistleyThere are at least 13 road overbridges , there are 11 road underbridges between Liverpool St and Stratford where steel trusses between the tracks prevent increasing the lower structure gauge width. Between Liverpool St and Romford there at least 13 road overbridges that have been there since the line was widened bnetween 1895 and 1902. These bridges have a very low clearance which resulted in the 1960 conversion from 1500VDC to ac involving the problematic intermediate use of 6.25kV ac as far as Shenfield. Much of the line from Liverpool St to beyond Chadwell Heath is in brick lined cuttings with little or no scope for additional land take to increase structure width. In other words, it would almost be a complete rebuild of a 20 mile long suburban high density corridor. I would give it at least 20 years to be completed with a drastic impact on services for most of that period and for what, - eventually an effective 10-20% increase in passenger capacity. Not very good value for money.

 

[Clip]

in my experience with buses stop dwell times per passenger are no better or worse for dd's than sd's and I'm sure that with one way flow through carriages that could, by and large be mitigated completely.

As to the amount of work needed.. I'm not advocating the WHOLE of the network being upgraded for DD's, but surely there's a route or 3 that are seriously overcrowded that could be converted to DD with minimal extra cost?

A bus can hold about 70 people. A train can hold a thousand. A terrible comparison to try and make.

 

[30907]

The key issue for the Bulleid Double Decker is that it wasn’t really double deck. It was a shocking example of design.

Look at German S Bahn / Regional Stock and it is a model of efficiency in people movement. Doors are approaching 2 metre wide allowing up to 4 people to disgorge at once and a big circulating space lets people in quickly.

The 4DD was ingenious but not thought through.

And IME DB double deck Regional trains are not particularly quick to load, and have extended dwell times at major stations. They make excellent medium distance commuter trains but aren't so good on inter-urban runs such as in the Rhine-Ruhr area where single deck stock seems to have come back into favour. S-Bahn sets are invariably single deck AFAIK.

 

[Teflon Lettuce]

A bus can hold about 70 people. A train can hold a thousand. A terrible comparison to try and make.

not really... a bus has {usually} one door... meaning 70 people per door... an 8 car train will have 2 doors per carriage... meaning 16 doors... 1000 passengers / 16 doors = 62.5 passengers per door.

 

[DenmarkRail]

I wouldn't be suprised if HS2 was built to a capacity to take double decker stock... Can HS1 take it?

 

[Bald Rick]

I wouldn't be suprised if HS2 was built to a capacity to take double decker stock... Can HS1 take it?

Yes x 2

 

[Agent_Squash]

not really... a bus has {usually} one door... meaning 70 people per door... an 8 car train will have 2 doors per carriage... meaning 16 doors... 1000 passengers / 16 doors = 62.5 passengers per door.

The Routemasters must have 3 for a laugh, then...

 

[DenmarkRail]

Yes x 2

So why don't we take advantage of this? Would be cheeper than buying trains especially modified for the BR network, givern how rare they leave their lines. I understand that HS2 trains have to be Classic Compatible to the WCML though.

 

[Bald Rick]

So why don't we take advantage of this? Would be cheeper than buying trains especially modified for the BR network, givern how rare they leave their lines. I understand that HS2 trains have to be Classic Compatible to the WCML though.

There aren’t any domestic service diagrams that are captive to HS1 though. In theory, if someone makes a double deck train that meets the necessary fire and security regulations for the Channel Tunnel, and platform heights for St Pancras / Ebbsfleet, then that could be done. But no one has yet.