Horses for Courses (or rolling stock choice)

[LE Greys]

To avoid various different threads veering off into debates about which classes of unit are suitable for which lines, I think I might start a specific thread to debate the issue. What precisely is each class for? This is my theory, although I'm sure other people have others. I'll start with DMUs.

If we carry on the way we are now, we will end up with 158s on the Norfolk branches, 170s on the Far North Line and 185s on Leeds-Morecambe, as each in turn is cascaded down after replacement by new stock. That might mean Voyagers on TPX, or Dellas on the Highland Main Line, which would be a waste of speed, horsepower and (remember this) fuel. While some of it sounds OK, is it a good idea? I think not.

I would never have a 158 booked for a turn where it can't exceed 75 mph at any point. That's partly because I think 156s are better units, but mostly because I think 158s do very well on compromise turns, where they can run at 90 mph on fast sections, then slow down for local services. Similarly, I would not have 170s on suburban stoppers (which is what 172s would probably be better for). There is enough work on secondary main lines and main/branch routes for both classes rather than allocate them to unsuitable duties.

Voyagers on TPX actually sound like a very good idea (we just need to produce some HST-quality units to replace them on XC) but 185s seem hideously overpowered for anything else. They might suit the Highland (steep gradients) or some semi-fasts in Devon (again steep gradients) but mostly they don't need 750 hp engines to run at 100 mph. 400 hp is fine for that speed.

180s are excellent for high-speed semi-fasts. I think they suited the Oxford Flyer very well, and Lincoln/Cleethorpes semi-fasts might just suit them as well.

Am I making any sense?

 

[WatcherZero]

The engines could always be derated if they couldnt be cascaded anywhere suitable. Increases fuel efficency at the cost of some power and speed.

Voyagers downrated from 750hp a car to 500hp and a 125mph top speed to 90-100mph?
185's perhaps could be left permanently in 'eco' mode and used somewhere flatter?

Im just suggesting their are other options than simple cascades.

 

[Pumbaa]

but 185s seem hideously overpowered for anything else. They might suit the Highland (steep gradients) or some semi-fasts in Devon (again steep gradients) but mostly they don't need 750 hp engines to run at 100 mph. 400 hp is fine for that speed.

hock: Do you have any idea how heavy the 185s are?! If you derated the engines to 400, they wouldn't move!! Seriously, they are heavier than most continents.

A move to Devon/Cornwall would suit the 185s well I think, and Cardiff - Portsmouth. Maybe even North Wales to supplement the 175s.

 

[ralphchadkirk]

but 185s seem hideously overpowered for anything else. They might suit the Highland (steep gradients) or some semi-fasts in Devon (again steep gradients) but mostly they don't need 750 hp engines to run at 100 mph. 400 hp is fine for that speed.

750hp is just fine - put 400 in and the driver would have to get out to push if it ever went over a molehill!

 

[ailsa]

On the line through Bath and Westbury we get a lot of 158s. There's also a lot of people getting on and off with pushchairs, children, dogs, boxes and bicycles, and the door position on the 158s doesn't make for a comfortable experience sometimes. There's not enough space without any seats. The FGW refurbished 150s with the drop down seats cope a lot better and in fact I think they've done a nice job.

Of course there's rumours that the 165s and/or 166s will be moving down here and I think they'll be much better suited to the route. Then again though, the 3+2 seating wouldn't be too good for passengers making the full journey from Cardiff to Portsmouth, or Gloucester/Worcester to Weymouth.

 

[Failed Unit]

If we base routes by speed then we better get the 185s off Cleethorpes to Manchester. They are lucky to get above 75mph with many areas 50mph and below. Ideally the route would have 3 car 170s. There are many too close to call. In the central trains day you could have Chester - Grimsby trains served by about anything they had. Most agreed the 150 and 153 was not suitable. However people could never really decide if they preferred to see the 158 or 156. For some reason the 170 was never as popular speaking with fellow passengers.

 

[tbtc]

Am I making any sense?

Complete sense

It frustrates me that the railway/ enthusiasts have no alternative to "buy newer faster stuff and cascade other trains down to more *local* routes".

When the Pacers go, we don't need to replace them with something 90mph capable with narrow doors - we need a 50mph train with wide doors and good acceleration/ breaks.

I'll have a good think about the "ideal" route for certain trains - this has got me thinking...

 

[LE Greys]

hock: Do you have any idea how heavy the 185s are?! If you derated the engines to 400, they wouldn't move!! Seriously, they are heavier than most continents.

I think that's mostly to do with the weight of the engines and associated drive train. I'm talking about a unit designed for 400-450 hp. Imagine putting a Lycoming IO-720 aero engine in a Ford Focus. You'd need a massive gearbox and huge tyres to cope with it. It would be a very fast Focus, but it would be very heavy and steer like a dog-sled. However, lots of power does suit a route with steep gradients, so 185s are useful rather than plain overpowered.
--- old post above --- --- new post below ---

When the Pacers go, we don't need to replace them with something 90mph capable with narrow doors - we need a 50mph train with wide doors and good acceleration/ breaks.

I wonder if it's possible to design a 'lightweight' version of the 172 (remembering the Derby Lightweight DMUs). Modify the gear ratios a bit (not sure whether mechanical or hydraulic transmission yet) and rely on that for acceleration. The only problem there would be the doors, which should really be at the ends of the vehicles - designed of course with DDA in mind.

 

[asylumxl]

I wonder if it's possible to design a 'lightweight' version of the 172 (remembering the Derby Lightweight DMUs). Modify the gear ratios a bit (not sure whether mechanical or hydraulic transmission yet) and rely on that for acceleration. The only problem there would be the doors, which should really be at the ends of the vehicles - designed of course with DDA in mind.

The 172s are designed to be "lightweight", most significantly the use of B5000 "lightweight" bogies from the 220s.

 

[455driver]

I think that's mostly to do with the weight of the engines and associated drive train. I'm talking about a unit designed for 400-450 hp.

Nope a Desiro carriage weighs tonnes more than needed, powered or unpowered

I wonder if it's possible to design a 'lightweight' version of the 172 (remembering the Derby Lightweight DMUs). Modify the gear ratios a bit (not sure whether mechanical or hydraulic transmission yet) and rely on that for acceleration. The only problem there would be the doors, which should really be at the ends of the vehicles - designed of course with DDA in mind.

The 170/172 body is already fairly lightweight anyway and the bogie's help it to remain light, end doors for express stuff but 1/3 2/3 for anything that has commuter/ local routes in mind, end doors on local routes just slows loading/ unloading.

 

[Pumbaa]

I think that's mostly to do with the weight of the engines and associated drive train. I'm talking about a unit designed for 400-450 hp.

Not really - they're just heavy full stop. The 185s are only 15 tonnes lighter (170 tonnes overall - 56 tonnes per car average) than a 220 Voyager (185 tonnes overall - 46.4 tonnes per car average); the Voyagers have the same engine, and a more complex and heavier drive system.

It's not the engines - its the fact they are tanks!

 

[tbtc]

I wonder if it's possible to design a 'lightweight' version of the 172 (remembering the Derby Lightweight DMUs). Modify the gear ratios a bit (not sure whether mechanical or hydraulic transmission yet) and rely on that for acceleration. The only problem there would be the doors, which should really be at the ends of the vehicles - designed of course with DDA in mind

That's the kind of thing that we need (though I'd put the doors nearer the middle rather than the end) - something fairly simple

Horses for Courses? I'd suggest that a 158 is the perfect unit for Cleethorpes - Sheffield - Manchester Airport.

1. No need for high speed running as the route isn't up to it
2. Decent seats needed as journeys are often up to an hour
3. Longer journeys mean doors at the end are okay
4. Corridor connections useful as some journeys require doubling up
5. There's the scope for First class on a route like this
6. It won't be electrified in the next twenty years or later
--- old post above --- --- new post below ---

Not really - they're just heavy full stop. The 185s are only 15 tonnes lighter (170 tonnes overall - 56 tonnes per car average) than a 220 Voyager (185 tonnes overall - 46.4 tonnes per car average); the Voyagers have the same engine, and a more complex and heavier drive system.

It's not the engines - its the fact they are tanks!

I think that in ten/ fifteen years time the 185s are going to be liabilities - units only really fit for one route (but not designed long enough to cope with that route).

 

[LE Greys]

Horses for Courses? I'd suggest that a 158 is the perfect unit for Cleethorpes - Sheffield - Manchester Airport.

1. No need for high speed running as the route isn't up to it
2. Decent seats needed as journeys are often up to an hour
3. Longer journeys mean doors at the end are okay
4. Corridor connections useful as some journeys require doubling up
5. There's the scope for First class on a route like this
6. It won't be electrified in the next twenty years or later

If they keep them in the same condition as Scotrail units, then that sounds fine. In fact, if electrification ever releases any Scotrail units, this is where they should go. Another possibility would be the 159s if SWT ever go for 100 mph units or something with a bit more power (unlikely for the moment). The 159s ought to be kept together if they ever move, so this might be a good place for them. The other option would be Cardiff-Portsmouth.

 

[Kingfisher200262]

The engines could always be derated if they couldnt be cascaded anywhere suitable. Increases fuel efficency at the cost of some power and speed.

Voyagers downrated from 750hp a car to 500hp and a 125mph top speed to 90-100mph?
185's perhaps could be left permanently in 'eco' mode and used somewhere flatter?

Im just suggesting their are other options than simple cascades.

You could always build some unpowered trailers, and form four car units.
--- old post above --- --- new post below ---

To avoid various different threads veering off into debates about which classes of unit are suitable for which lines, I think I might start a specific thread to debate the issue. What precisely is each class for? This is my theory, although I'm sure other people have others. I'll start with DMUs.

If we carry on the way we are now, we will end up with 158s on the Norfolk branches, 170s on the Far North Line and 185s on Leeds-Morecambe, as each in turn is cascaded down after replacement by new stock. That might mean Voyagers on TPX, or Dellas on the Highland Main Line, which would be a waste of speed, horsepower and (remember this) fuel. While some of it sounds OK, is it a good idea? I think not.

I would never have a 158 booked for a turn where it can't exceed 75 mph at any point. That's partly because I think 156s are better units, but mostly because I think 158s do very well on compromise turns, where they can run at 90 mph on fast sections, then slow down for local services. Similarly, I would not have 170s on suburban stoppers (which is what 172s would probably be better for). There is enough work on secondary main lines and main/branch routes for both classes rather than allocate them to unsuitable duties.

Voyagers on TPX actually sound like a very good idea (we just need to produce some HST-quality units to replace them on XC) but 185s seem hideously overpowered for anything else. They might suit the Highland (steep gradients) or some semi-fasts in Devon (again steep gradients) but mostly they don't need 750 hp engines to run at 100 mph. 400 hp is fine for that speed.

180s are excellent for high-speed semi-fasts. I think they suited the Oxford Flyer very well, and Lincoln/Cleethorpes semi-fasts might just suit them as well.

Am I making any sense?

Perfect sense, as far as engine power goes. However, door position, aperture width and seating layout are also issues that should be considered when deciding which rolling stock is suitable for which duties.

 

[455driver]

The engines could always be derated if they couldnt be cascaded anywhere suitable. Increases fuel efficency at the cost of some power and speed.

Voyagers downrated from 750hp a car to 500hp and a 125mph top speed to 90-100mph?
185's perhaps could be left permanently in 'eco' mode and used somewhere flatter?

Im just suggesting their are other options than simple cascades.

But to alter the top speed after de-rating the engine means altering the gearing which will be very expensive or if you left the gearing it would lower the acceleration rate more than the top speed, but of course you could just put a new sticker in the cab

I also think any new multiple units should be fitted with end gangways as a matter of course.

 

[LE Greys]

Now, let's consider EMUs as well.

We need to replace the 313s/4s/5s fairly soon. I'm slightly concerned that we will end up with various forms of outer-suburban stock coming in instead. There's also the fact that not very much can fit down the Moorgate tunnels. We have 317s slowly taking over inner suburban duty out of Liverpool Street, which I don't like because of acceleration issues yet we don't have 321s on Cambridge turns. Then in SWT territory, there is the opposite issue of suburbanisation of the Portsmouth Direct, while high-density 450s could cope with some 455 duties. SWT needs more 444s (perhaps fitted with seats from 375s, interior fans and aluminium window frames ). However, the rest of the 455s need replacement as well, so will we get a standard type of inner suburban unit any time soon?

I also think any new multiple units should be fitted with end gangways as a matter of course.

Agree there, having two non-gangway units run together either requires extra staff or causes problems. Might be a bit tricky with 125 mph units, but they should never be shorter than six coaches anyway.

 

[Bastiaan]

so will we get a standard type of inner suburban unit any time soon?

Yep. Siemens is promoting the Desiro City, Bombardier does the same for the Capitalstar (class 378 ) and recently Alstom has unveiled it's new X'trapolis UK.

 

[WatcherZero]

Hasnt Alstroms already been eliminated from Thameslink negotiations just leaving Desiro and Electrostar mk2? With Crossrail and Thameslink saying they will save costs with a single design whoever wins is going to have the market tied up for the next generation.