HOW do trains 'turn around' at St. Pancras

[RichmondCommu]

The fact that four GWR trailers are at Wabtec for conversion, plus 43194 there as well (to have the interlock mods done), is a bit of a giveaway, is it not?

Well it is now you've told me.

 

[RichmondCommu]

Surely Wabtec at Doncaster are already working on the first coaches, unless I've been misinformed.

I wasn't aware of that but I am now

 

[suzanneparis]

Separate but slightly related question. I used to have to catch the Leicester to Stanstead train. But it was often just two carriages and crowded - obviously going to an airport.

I asked a member of staff why they didnt put one or two extra carriages in the middle of the train (it had a drivers bit at both ends). He said it wasn't possible because they were made like that.

Is that true ?

 

[jopsuk]

Separate but slightly related question. I used to have to catch the Leicester to Stanstead train. But it was often just two carriages and crowded - obviously going to an airport.

I asked a member of staff why they didnt put one or two extra carriages in the middle of the train (it had a drivers bit at both ends). He said it wasn't possible because they were made like that.

Is that true ?

Sort of. Turbostars have been built with 2, 3 and 4 carriages. But all the carriages have to be powered Turbostar carriages- you can't take two (say) Mark 3 carriages and stick them in the middle, Turbostars are under powered as it is

 

[suzanneparis]

BUT... I thought one of the many advantages of train was that metal wheels on metal track means very little rolling resistance. Hence shoving a couple of extra (unpowered) carriages in the middle of a two carriage Turbostar shouldn't make much difference to the performance.

Or have I got that terribly wrong..............??

 

[najaB]

Or have I got that terribly wrong..............??

You're correct that there's little rolling resistance, but the carriages still have mass and hence inertia. It takes energy* to get them moving and a Turbostar doesn't really have much going spare.

Edit: *Okay, it takes a force to get them moving.

 

[GW43125]

BUT... I thought one of the many advantages of train was that metal wheels on metal track means very little rolling resistance. Hence shoving a couple of extra (unpowered) carriages in the middle of a two carriage Turbostar shouldn't make much difference to the performance.

Or have I got that terribly wrong..............??

By doing that, first of all you'd immediately half the power-to-weight ratio. This can cause issues on hills.

Secondly, there are no vehicles you could put in the middle. Standard carriages would not work for a number of reasons, most notably the different braking systems. A unit is a unit and stays like that.

 

[Lampshade]

BUT... I thought one of the many advantages of train was that metal wheels on metal track means very little rolling resistance. Hence shoving a couple of extra (unpowered) carriages in the middle of a two carriage Turbostar shouldn't make much difference to the performance.

Or have I got that terribly wrong..............??

The engines are way too underpowered, managing to be frenetic yet ineffectual, like a hamster pushing a filing cabinet.

 

[edwin_m]

like a hamster pushing a filing cabinet.

That thought has cheered me up on a cold morning...

 

[suzanneparis]

Ah.... I see. Many thanks to all.

Separate separate question. Why don't they produce units that can be easily made into longer or shorter trains but which are cheaper to manufacture. Perhaps even a Turbostar with a bigger engine??

Thanks agaain. I find this topic interesting.

 

[GW43125]

Ah.... I see. Many thanks to all.

Separate separate question. Why don't they produce units that can be easily made into longer or shorter trains but which are cheaper to manufacture. Perhaps even a Turbostar with a bigger engine??

Thanks agaain. I find this topic interesting.

They do. That's the point of multiple units. You can couple them together.

 

[Dr Hoo]

To continue the explanation...

By coupling units 'in multiple' (that is why they are called "multiple units") the power-to-weight ratio remains almost constant and thus the train can keep to the same schedule/point-to-point timings. This is essential on a busy rail system that can only function reliably if every train is capable of complying with the timetable.

The problem with services like Birmingham-Stansted services is that there are (broadly) no spare similar multiple units available anyware to actually make multiple formations possible on most trains.

 

[sprinterguy]

Additionally, opportunities to insert additional vehicles into existing units to extend them can be hamstrung by:

• The incompatibility of differing train management systems or electrical connections,

• Changes in emission regulations making it difficult to order additional compatible powered vehicles,

• Closure of production line,

• Financial or political will to purchase additional carriages

In theory, it shouldn't be impossible for a manufacturer to produce a multiple unit with fairly standardised train management and electrical systems to permit the insertion of additional vehicles in the future from any manufacturer, and with engines large enough to allow the future addition of unpowered vehicles, but where's the benefit to the manufacturer from such an arrangement, or to the train operator in increased fuel usage only for the sake of a future possibility? Plus, who's to say that the standards in train management or electrical systems wouldn't change again in the near future, making the whole intention redundant? It would take a centralised rolling stock planning policy, and/or stringently applied standards, to make such a thing a reality.

 

[najaB]

Separate separate question. Why don't they produce units that can be easily made into longer or shorter trains but which are cheaper to manufacture. Perhaps even a Turbostar with a bigger engine??

Because it is easier, cheaper and faster to couple entire sets - e.g. two threes making a six - than it is to go through the process of uncoupling the end carriages, driving them off somewhere else to wait, attaching intermediate carriages and the bringing the end carriage back and reattaching it.

Edit: Must remember to read to the end of the thread before replying.

 

[Taunton]

Separate separate question. Why don't they produce units that can be easily made into longer or shorter trains but which are cheaper to manufacture.

That was done a generation ago. They were called the "Modernisation Plan" units. Thousands of cars were produced, they were affordable, there were sufficient for strengthening services where required, and they lasted 30 or more years.

However, it was determined to replace them with a fraction of the number of cars, much higher priced, with harder and more squashed-up seating (for the few lucky enough to get a seat), while well-paid technical designers came up with different coupling connections that meant that even trains which looked otherwise identical couldn't be coupled together. You couldn't make it up. So I didn't. It's true.

 

[najaB]

You couldn't make it up. So I didn't. It's true.

Well, it's not false.

 

[yorksrob]

That was done a generation ago. They were called the "Modernisation Plan" units. Thousands of cars were produced, they were affordable, there were sufficient for strengthening services where required, and they lasted 30 or more years.

However, it was determined to replace them with a fraction of the number of cars, much higher priced, with harder and more squashed-up seating (for the few lucky enough to get a seat), while well-paid technical designers came up with different coupling connections that meant that even trains which looked otherwise identical couldn't be coupled together. You couldn't make it up. So I didn't. It's true.

To be fair, we often see many interesting combinations of pacers, sprinters and super-sprinters, so compatibility was being done with the later BR DMU's.

 

[6Gman]

Separate but slightly related question. I used to have to catch the Leicester to Stanstead train. But it was often just two carriages and crowded - obviously going to an airport.

I asked a member of staff why they didnt put one or two extra carriages in the middle of the train (it had a drivers bit at both ends). He said it wasn't possible because they were made like that.

Is that true ?

Yes.

They could have been built as 3car units, but that would have cost c.50% more.

Or as 4car units, but that would be c.100% more expensive.

The days when you could just stick an extra coach or two onto a train are long gone.

 

[cjmillsnun]

To be fair, we often see many interesting combinations of pacers, sprinters and super-sprinters, so compatibility was being done with the later BR DMU's.

Ahh but try and couple them to 165s or 166s

 

[Ianno87]

Yes.

They could have been built as 3car units, but that would have cost c.50% more.

Or as 4car units, but that would be c.100% more expensive.

The days when you could just stick an extra coach or two onto a train are long gone.

And you have to pay the cost of carting those extra carriages (with engines and fuel) round all day, every day, even when demand does not require it.

 

[yorksrob]

Ahh but try and couple them to 165s or 166s

Yrs, it went a bit awry towards the end.

 

[MarlowDonkey]

Ahh but try and couple them to 165s or 166s

Was there a good technical reason for this? Was it just internal rivalry inside British Rail so stop the competition, any part that wasn't Network South East, from using these then brand new units?

 

[jopsuk]

As far as is known, yes, it was simply NSE putting a barrier in the way of Regional Railways.

Of course, NSE managed to nab what became the 159s off RR (roughly)- if everything had gone to plan for both divisions it would have been Networkers for the South West too.

 

[70014IronDuke]

Never seemed to do me and my colleagues any harm.

One of my pals, who worked in a PW gang for a few months (back-breaking work, he said, took him a month to get used to it) told me the gang would always turn their backs to passing trains, angled slightly in the direction of travel, to avoid any sh*t hitting them in the face.

 

[70014IronDuke]

sub question. Do trains at St P get refuelled in the station and have their toilets emptied? And how long does that take?

re refeulling: Think of the risks involved mixing unwary passengers with refuelling equipment, problems with spillage, etc Far better to keep the two operations of loading/unloading and refuelling (and anything but minimal maintenance) separate.

 

[Taunton]

re refeulling: Think of the risks involved mixing unwary passengers with refuelling equipment, problems with spillage, etc Far better to keep the two operations of loading/unloading and refuelling (and anything but minimal maintenance) separate.

Which never stopped the transcontinental lines in USA and Canada having refuelling (and watering for the steam heating) points for the locomotives at the front end of key station platform.

They could have been built as 3car units, but that would have cost c.50% more.

Or as 4car units, but that would be c.100% more expensive.

A cost analysis I saw showed that the driving cab and its connections and fittings can be 15-20% of the vehicle cost. Trailer = no cab.

If the engines on the cab cars are specified sufficiently powerful to handle a trailer as well, that is a very substantial reduction in cost and weight.

 

[tsr]

As far as is known, yes, it was simply NSE putting a barrier in the way of Regional Railways.

Of course, NSE managed to nab what became the 159s off RR (roughly)- if everything had gone to plan for both divisions it would have been Networkers for the South West too.

Network Turbos (and Turbo Expresses) always seemed to me to be rather less spiteful than that - just very much the first phase of the introduction of units designed to make the most of what the suburban routes around London could handle, providing large coaches, plenty of seating and sensible door arrangements, as well as impressive future-proofing which has enabled them to be used in a variety of different crewing arrangements, and with varying arrangements for luxuries like First Class and catering, too. Effectively they have proved to be an excellent catch-all design, much like a Swiss army knife of a train, into which there was a lot of research, and from which evolved some of the very most comfortable modern DMUs, such as 168s and 171s. I'd go so far as to say that the evolution of the design has meant that the expanding family became anything but NSE-only units.

One of my pals, who worked in a PW gang for a few months (back-breaking work, he said, took him a month to get used to it) told me the gang would always turn their backs to passing trains, angled slightly in the direction of travel, to avoid any sh*t hitting them in the face.

A good move in many cases! \Something still done by longstanding staff in areas from which regular workings of non-CET stock have long since vanished.

re refeulling: Think of the risks involved mixing unwary passengers with refuelling equipment, problems with spillage, etc Far better to keep the two operations of loading/unloading and refuelling (and anything but minimal maintenance) separate.

It's also wise to do it as far as possible from electric traction systems which may emit sparks. That said, OHLE (as at St Pancras) and diesel is better than some combinations of fuel and electricity.

A cost analysis I saw showed that the driving cab and its connections and fittings can be 15-20% of the vehicle cost. Trailer = no cab.

If the engines on the cab cars are specified sufficiently powerful to handle a trailer as well, that is a very substantial reduction in cost and weight.

Whilst such flexibility is in place with some units, especially some Southern region/area EMUs, some DMUs such as Turbostars have a job keeping time with anything under 100% performance, right down to variations within fuel quality and mileage within the maintenance schedule, and all this without worrying about trailers. As has previously been pointed out, the engines are not really powerful enough to provide an efficient service whilst dragging trailer cars.