Can’t think of a better community to ask.
The main downside of double-decker train cars is the time it takes passengers to to board them. And, since this is one of the main factors limiting metro frequencies and thus capacity, they’re not that suitable for subways. To maximize metro capacity, you want long trains with many doors and very high frequency.
Double-decker cars are much more suitable for lower-frequency service (S-Bahn, regional, long-distance,…) where they’re also commonly used.
Of course, you could still use double-decker cars in a metro (and maybe some places do), it’s just suboptimal.
Two level platform? Then you’re actually boarding double the number of passengers, could be useful in very busy stations.
It sounds like a weird idea at first, but maybe it could actually work. Kind-of like running two trains on top of each other instead of after each other. I guess the downside would be the need for bespoke rolling stock and larger platforms. I think, it would generally be preferable to double the frequency or run longer trains. But it could be interesting if you’ve already exhausted those.
There’s a balance to be made between the flow of people and the seating capacity of trains.
Single level with many doors will load/unload quickly, however there’s barely any seating. Two level maximizes seating at the expense of dwell times.Nobody made a two level train with a focus on standing yet, so we don’t have a real world example. If it’s even possible because you need more headroom than usually available on double deckers
That said there are metro-like systems with double deckers. Paris and Sydney have already been mentioned. True, they are usually classified as suburban systems, but are very much used for city trips as well.
I think one of the bigger things keeping metro rolling stock from using double decker units is the need to go underground. Increased height means larger tunnels or deeper cuts and that can get cost prohibitive. This is especially the case when simply lengthening the tunneling needed for longer station boxes/platforms to support higher capacity single deck trains is less costly.
I thought this was a different community for a minute, and got really excited 😫
Hungry?
I wasn’t until I read the post 😁
Some subway cars in Sydney are double decked. The seats are a half floor up or down from where the doors open.
No one has mentioned the idea of having double-decked stations to make it so you don’t have to worry about moving to the right floor in advance of your stop.
I would posit this as a given if we bothered to make taller tunnels for taller train-cars, but based on other comments here, I’m not sure this idea actually makes the concept of double-decker subways any more sensible or useful.
It looks like those metros that have a use for the idea have made it work in their own way and places that haven’t tend to have significant reasons of their own for not going this route. Enlarging existing tunnels vertically seems to be a non-starter in most places, for instance.
New York has some of the longest subways at 600ft (160 meters)
Next up is shanghai and Beijing.
Paris is 6th.
So we could go longer but maybe more frequent is better?
High-frequency systems with shorter trains are often more effective at moving passengers quickly during peak hours, because the trains come more often, reducing platform overcrowding and wait times. For example, the Tokyo Metro system, despite having relatively shorter trains compared to New York, serves a much higher passenger volume because of its incredibly high frequency and reliability.
What I’m thinking is double decker lets people who are going through the downtown (so cities not on the coast) to be out of the way.
I dunno where you live but Metra in Chicagoland (connecting the city center to the surrounding suburbs) are double decker already. The L trains downtown don’t really need them.
Metra is more of a commuter system than a metro system… but when looking at systems like San Francisco’s BART, the line between a metro and a commuter railway gets blurry.
The problem is that you need very tall tunnels for that. Subway tunnels are usually some of the narrowest tunnels in order to be cheaper to construct and the trains are built to be accordingly small too (an extreme example being the deep-level London Underground lines).
There’s nothing technically unfeasible about it. Underground railways with double-decker trains are a thing already, I commute through this station every day, though usually with a single-decker train; this is a mainline railway served by both single-decker and double-decker trains (the latter pulled by heavy locomotives, you can’t see that on the other photo because that is the other end of the train).
Most subway lines were dug after the city they go under was built, and, for example, there’s a whole lot of London on top of the London Underground. Very difficult to dig upwards, very expensive to dig downwards. In the above ground sections you’d have to rebuild all the road bridges.
Much easier and cheaper to run the most efficient service possible with a high throughput of trains.
As in a traincar with a staircase inside, or as in two stacked rail tracks in parellel along a subway route?
The passenger trains connected to Chicago Union are bilevel
Oh, I like this. Put the second rail right on top of the cars for the real express line.
Here in Boston a lot of the commuter rail cars are double decker. I guess it’s an upgrade to carry more people rooms but a better upgrade would be running more trains. That costs money though
Like other people said, I don’t know about subway. You want to be quick on quick off. I don’t usually even sit (even when there’s room )
I went on the Naples subway once, and they were running full size 2-deck commuter trains on the subway. It was way overkill.
