Why are mainline trains narrower than London Underground sub-surface stock?

[Lanehogger]

Apologies if this sounds like a really daft question.

I know the UK loading gauge is quite restrictive compared to many other standard gauge railways, but does anyone know why mainline rolling stock is narrower than London Underground's sub-surface stock?

I initially thought it was because the loading gauge was larger on the underground network, but the new S-Stock was delivered along the mainline network, while some stations in London are served by both mainline and sub-surface stock. For example, a Turbostar is almost a foot narrower than the S-Stock, as well as being narrower than the older A, C and D-Stocks. Electrostars are narrower too. Extra width would liberate more shoulder room on seats, or make gangways wider.

 

[HSTEd]

The intermediate vehicles on the S-Stock are only 15-16m long, compared to 23m for Turbostars.

This is the primary reason.

 

[deltic1989]

This may sound like a daft answer but.
My impression was that LU stock is wider so they could fit more people on.
I stand to be corrected though.

 

[route:oxford]

The intermediate vehicles on the S-Stock are only 15-16m long, compared to 23m for Turbostars.

This is the primary reason.

So...

Could the S-Stock design in a 3-car format be a suitable replacement for the Pacer?

With more seats and an underfloor diesel package...

 

[Simon11]

So...

Could the S-Stock design in a 3-car format be a suitable replacement for the Pacer?

With more seats and an underfloor diesel package...

The shorter the carriage, the wider the carriages can be to handle the curves.

 

[Chris125]

Could the S-Stock design in a 3-car format be a suitable replacement for the Pacer?

Not really. Pacer's will be replaced by other cascaded DMU's, a new design is unlikely in the near future and any future design will almost certainly continue the trend to maximise the body length.

Chris

 

[Class377/5]

Apologies if this sounds like a really daft question.

I know the UK loading gauge is quite restrictive compared to many other standard gauge railways, but does anyone know why mainline rolling stock is narrower than London Underground's sub-surface stock?

I initially thought it was because the loading gauge was larger on the underground network, but the new S-Stock was delivered along the mainline network, while some stations in London are served by both mainline and sub-surface stock. For example, a Turbostar is almost a foot narrower than the S-Stock, as well as being narrower than the older A, C and D-Stocks. Electrostars are narrower too. Extra width would liberate more shoulder room on seats, or make gangways wider.

If your talking about widths its to with fact line was built (well the Met) with both UK guage and broad guage. This means some parts are bit more spacious than others where the Turbo and Electro stars are both designed to be a common UK design so were build to run pretty much anywhere on the UK not limited but better space guage like the Met A stock was.

 

[ChiefPlanner]

The "A" stock was very wide , build to the "Met" gauge (remember Edgware Rd - Farringdon was broad gauge when built !) - this caused problems when towing them north for the refurb in the 1980's as a special gauging run had to be done.

 

[northwichcat]

So...

Could the S-Stock design in a 3-car format be a suitable replacement for the Pacer?

With more seats and an underfloor diesel package...

Not really. Pacer's will be replaced by other cascaded DMU's, a new design is unlikely in the near future and any future design will almost certainly continue the trend to maximise the body length.

Chris

3 carriages of 15m in length would make a 45m long train which is only slightly shorter than a 2 car 172. Why create a new concept when an existing concept can do the job?

 

[rebmcr]

Not to mention the fact that underfloor diesels that comply with new emissions regulations don't exist — and there's no room underneath an S Stock for one anyway.

 

[jopsuk]

Not to mention the fact that underfloor diesels that comply with new emissions regulations don't exist

At the moment. I think the main reason that there isn't one is not that it can't be done, it is that the engine manufacturers currently see little point in doing the R&D required.

 

[route:oxford]

Not to mention the fact that underfloor diesels that comply with new emissions regulations don't exist — and there's no room underneath an S Stock for one anyway.

It's a shame that there is no-one skilled enough in Europe to design an engine that meets European specifications.

If there were, would it be possible to obtain a grant to build them in the UK?

 

[jopsuk]

Why would anyone design something that there's clearly no actual market for? Government and industry have sent out signals that there's to be no new DMUs for the UK for quite some years. So why would anyone spend time and money designing an engine that no desicion-maker actually intends to buy?

 

[Chris125]

At the moment. I think the main reason that there isn't one is not that it can't be done, it is that the engine manufacturers currently see little point in doing the R&D required.

As the recent rolling stock strategy says, it will be "increasingly...difficult or even impossible to procure and operate new DMUs having underfloor diesel engines, with an affordable business case" - from what's been said over the years, the situation is complicated not only by the lack of sizeable orders but the likely size of a suitable compliant engine.

Chris

 

[jopsuk]

chicken and egg situation. There's no orders for new DMUs so there's no engines developed for them, but with no engines developed for them the cost of new DMUs goes up (due to lack of continuous development) which makes orders for new DMUs less likely.

I don't accept that it "can't" be done. Designers of engines for cars etc are getting more and more power out of (physically) smaller engines whilst working to broadly the same emissions regulations.

 

[euryalus]

I thought that modern dmus such as the "Voyagers" are narrow because some of them were designed to tilt? This requirement seems, however, to have applied even to the non-tilting trains. Class 165 and 166 units, on the other hand, are 2.81 metres wide, which is quite generous - but then of course they were properly-designed and built in the UK for use on what was then a nationalised railway system. To my mind, the introduction of cheap and nasty foreign trains that are far too narrow was an inevitable concomitant of privatisation.

 

[swt_passenger]

Voyagers are not actually significantly narrower (at their widest point IYSWIM) than any other '23m' stock, they are described as 2.73m compared to the more typical 2.74m. So a bit wider than a 444, which IIRC is the narrowest 23m stock around at 2.688m (according to the end labels).

Voyagers do, on the other hand, have a significantly different body shape to non-tilting trains - and I believe the internal linings take up a massive amount of room.

 

[euryalus]

No, Voyagers are not that much narrower at the widest point, but I think the problem is caused because they become narrower at around the shoulder height of an average person.

 

[swt_passenger]

No, Voyagers are not that much narrower at the widest point, but I think the problem is caused because they become narrower at around the shoulder height of an average person.

So what is the actual problem you write about?

It would be a much bigger problem if they hit the infrastructure or other trains while tilted...

 

[euryalus]

So what is the actual problem you write about? It would be a much bigger problem if they hit the infrastructure or other trains while tilted...

The problem, as far as I was concerned, was that they were shorter and had much less interior space than the HST sets which they replaced on long-distance cross-country services. This was widely seen as a retrograde step.

 

[route:oxford]

I don't accept that it "can't" be done. Designers of engines for cars etc are getting more and more power out of (physically) smaller engines whilst working to broadly the same emissions regulations.

Exactly.

Perhaps the problem isn't upgrading an existing "industrial" engine to meet emissions regulations...

Instead a highly efficient car engine could be upgraded to "industrial" standards.

 

[sprinterguy]

I thought that modern dmus such as the "Voyagers" are narrow because some of them were designed to tilt? This requirement seems, however, to have applied even to the non-tilting trains. Class 165 and 166 units, on the other hand, are 2.81 metres wide, which is quite generous - but then of course they were properly-designed and built in the UK for use on what was then a nationalised railway system. To my mind, the introduction of cheap and nasty foreign trains that are far too narrow was an inevitable concomitant of privatisation.

The class 165 and 166 units were built to take advantage of the more generous Great Western loading gauge and are not representative of other 23 metre long rolling stock - As swt_passenger says, mark 3s are only 1cm wider than a Voyager. They are therefore somewhat restricted in the routes that they can operate over at present, and a range of gauge enhancement works will be required to clear them for other routes across the West Country that they are expected to be cascaded to following GWML electrification.

 

[northwichcat]

The class 165 and 166 units were built to take advantage of the more generous Great Western loading gauge and are not representative of other 23 metre long rolling stock

Apart from the class 323s which have 23.4m carriages and a 2.8m car width.

 

[sprinterguy]

Apart from the class 323s which have 23.4m carriages and a 2.8m car width.

Good point, I hadn't realised that.

 

[asylumxl]

Apart from the class 323s which have 23.4m carriages and a 2.8m car width.

As far as I'm aware, it was designed as a "go anywhere" profile and make the maximum use of the loading gauge allowed.

Shows what a bit of thought can do.

 

[The Ham]

Exactly.

Perhaps the problem isn't upgrading an existing "industrial" engine to meet emissions regulations...

Instead a highly efficient car engine could be upgraded to "industrial" standards.

What like a bus or lorry engine, which must have to meet certain emission standards. If the underfloor engine only has to keep time with a pacer, then I would have thought that would be fine as some of them where built by bus builders in the first place.

 

[HSTEd]

There are underfloor engines that do meet current emissions regs (see the IEP).

They are rather high powered for a DMU however....

 

[The Ham]

There are underfloor engines that do meet current emissions regs (see the IEP).

They are rather high powered for a DMU however....

Cool a 110mph pacer!

 

[euryalus]

The class 165 and 166 units were built to take advantage of the more generous Great Western loading gauge and are not representative of other 23 metre long rolling stock.

Yes, I have read that somewhere, but is it actually true? The class 158s, which were not built to the GWR loading gauge, are slightly wider than the class 165 and class 166 units. In fact, all of the British-built "new generation" dmus seem to be about 2.81 metres in width.

 

[sprinterguy]

Yes, I have read that somewhere, but is it actually true? The class 158s, which were not built to the GWR loading gauge, are slightly wider than the class 165 and class 166 units. In fact, all of the British-built "new generation" dmus seem to be about 2.81 metres in width.

No they're not. 158s are 2.7 metres wide. That is the same as the Leyland Sprinter classes while the 156s are slightly wider at 2.73 metres.