Just been on a run from Hamburg to Hanover in TS which got me thinking. Why in the UK have we not adopted the twin - deck approach to our regional commuter trains? Getting in and out of London and most other major cities at morning and evening rush hours is a nightmare, with more and more commuters being jammed into over crowded, single deck trains when the rest of Europe and the wider world have gone for :- Just wondered if there was any rationale or physical reason why we here in Britain haven't gone down this route???
The loading gauge in the U.K., in large part due to our old Victorian era tunnels, is too small to accommodate the larger two deck cars.
But over across the pond we were able to make bi-level cars fit into Penn Station/North and East River Tunnels, which are the lowest clearance locations in the US. Surely the UK couldn't give a try either? For example, the BR Class 47 is 12'9", while these cars are 14'5" surely with some creative engineering, one can shave off 1 foot.
I think it would just cost too much. We have a heck of a lot of tunnels across the network. I guess it could be done if really necessary, but I don’t think there is sufficient appetite or funding to do it.
Most people will know of the Class 66 loco which can be seen in the UK and in Europe The Class 66 was designed to fit inside the UK Loading Gauge and when you see one with European wagons you realise how much smaller they are and how difficult it would be to have Double Deck Stock The Cab Air Cond units are out of Gauge for UK running and when one came to the UK they had to be removed The Class 77 EM2 locos were sold to the Dutch Railways in 1970 and ran in mainline service until 1986. In 1989 the first loco in the Class 27000 Electra went back to Holland to works some specials and included a run with Double Dec stock The height difference is noticeable But how wide are they? It used to be a maximum of 9'3" wide on UK railways and still is in places
Basically, we'd need to rebuild half the network to have double-deck trains here. Heck we've got a lot of places which don't have enough room for overhead electric lines as it is.
Maybe we're looking at this the wrong way; instead of making the trains taller, how about making the people shorter?!
For a more modern comparison in TS, here's a 377 and 450 (2 of the most common units in South london, where I'd argue DD trains are most useful) next to a German Dosto Cab Car.
Height is okish, but might be tight in the corners. Bigger problem is our platforms and other gubbins mean that UK stock has to get very narrow below the floor, whereas in many other places the full width is available almost to rail level. A good example is the FLIRTS on GA, which have a very noticeable kink in the sides because their low floors are in the narrower part of the loading gauge. These for example will fit UK Height, but platforms and other stuff here would intrude into the lower deck. Only solution I can think of is to fit go anywhere stock with retractable gap fillers and trim platforms back - but then there are other structures (bridge girders etc) that may not be so easily modified
The Hastings line is particularly restrictive thanks to a tunnel. A coach body from the Hastings line was used in tests for APT systems because it could tilt and still be within gauge. Anyone who has the Weardale and Teesdale route will be familiar with Shildon tunnel- IRL it was singled in the early days of BR because it was too tight for trains to pass safely.
In the late '50s or '60s I thought but don't remember where I got that from and the only reference I can find now suggests it was earlier- perhaps pre-Nationalization. Apparently to mitigate against the bottle-neck it was common practice to couple two or three freight trains together so they could go through as one working.
Might be the introduction of longer coaches. UK tracks hug each other very much, bridges are just about tall enough, Woodhead tunnels had to be remade, the London Underground is famously clumsy. I wouldn't be surprised if everything was made as small as possible, even the tiniest difference causing trouble. By the way, the old long tunnel on Canadian Mountain Passes also used to be double track, but cut down to single when rolling stock got larger. So while I love to make puns about Toy Train Network, the situation is not unique But, where money speaks, it's done. I suppose HS1 could have bilevels not because it's necessary, but because it's built / upgraded to EU gauge standards. Bilevels fit shorter platforms, so that's a plus, it's not necessary about the capacity - but, they can be made more spacious. One potential issue of UK bilevels is that they're not wheelchair friendly, but also include your bags and what have you. The entry level is between the two floors, of course it's possible to have some seats, but then you have to take many steps to cross from one wagon to the next. Otherwise a bit of a ramp is enough with Jacobs bogies. And as some mentioned, the high platforms across the UK, while very useful in every other aspect, are an issue about this. They can be changed, but then existing stock will be like good old Newcastle-York. Mind the gap. I mean chasm.
The UK did have the SR Class 4DD, which was a split level train more than a double decker, but it's the closest thing to a double decker train that ran in the UK, and the only train that could be considered to be a UK double decker train. 2 train sets were built, each with 4 cars, to serve on commuter services between London and Dartford, operating between 1949 and 1971. They were considered a failure due to poor mechanical reliability and poor passenger comfort, partly due to the cigarette smoke that would accumulate in the upper seating areas. (Smoking was still allowed on trains when these were operating.) 2 DMBT cars have survived into preservation.
