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Author Topic: Problems with the Night Riviera sleeper - December 2014 onwards  (Read 251052 times)
stuving
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« Reply #840 on: January 26, 2021, 11:36:57 pm »

Yes it supplements the Diesel engine.  Probably to help get it going at lower speeds and kick in again if necessary when tackling the steeper gradients.  The sleeper is not a particularly heavy or fast train - given the stated ambition of hauling freight trains as a mixed traffic loco - so perhaps it would be fine?

Yes, but ... some order-of-magnitude numbers:

Pick a typical Devon bank of about 130 m rise in 8 km distance and a line speed of 60 mph (27 m/s)
Converting that rise into a velocity with equivalent energy (640 MJ) gives 50 m/s - much more, so taking a run at it won't get you very far (literally)
Also, 640 MJ is 180 kWh - much more than the 80 kWh in the batteries
Done at full speed, that run would take 5 minutes, and the power needed to keep speed against gravity is 2.1 MW - so the diesel's 900 kW doesn't allow this either.
The best you could do, assuming the battery could provide enough to overcome friction and drag, with 900 kW is 12 minutes - 40 km/hr (25 mph)

So a battery that size comes under the "every little helps" category.

For a goods train of 1500 t the effect on hill-climbing is, of course, even more marginal. But for accelerating to speed (where the energy needed is more limited) things are a bit better. Looking at the time to reach 60 mph with diesel alone and with diesel+battery (and ignoring friction and drag altogether), I get 10 minutes and 7 minutes. And that doesn't drain the battery (it's less than 12 minutes).

But I think you can see why fitting batteries of a useful size to any train is a challenge, and in a locomotive it's going to be on the impossible side of very difficult for some time.

PS: E&OE excepted - and not unlikely, as that was done very quickly, so if you can spot anything wrong do say

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stuving
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« Reply #841 on: January 27, 2021, 08:44:34 am »

But I think you can see why fitting batteries of a useful size to any train is a challenge, and in a locomotive it's going to be on the impossible side of very difficult for some time.

On second thoughts, that's too pessimistic. The big issue is the capacity of the batteries, and that is low even by current hybrid (road) vehicle standards. So why, could a big increase be possible soon, and if it is so limited what is it there for?

The answer to the last question must be for regenerative braking - and the batteries do replace the braking resistors in the precursor design. So it's put there to take in the kinetic energy when slowing down, and give it back again soon after. Once it's full, only friction braking is available. One implication of this is that it will not be kept full - the obvious strategy is to keep it half-full, so as to be ready for braking and for accelerating.

Future battery technology is very much a guessing game. So far, high-power applications like trains have been hard to do, and I take it that's why this one has a lower capacity/power ratio than one in a car. So a big change in that limit would alter the calculations for a hybrid, but only a very big change would make a "mains/battery" loco a go-anywhere replacement for a diesel.
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TaplowGreen
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« Reply #842 on: January 27, 2021, 09:00:36 am »

I wonder what sort of a future the sleeper will have in the "New World" post COVID?

I guess its use by MPs (Member of Parliament) from the South West may help to keep it going, but with the expected fall in business travel one does wonder if it will be sustainable, and/or whether the authorities will be prepared to offer more subsidy to maintain it if passenger numbers fall further?
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eXPassenger
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« Reply #843 on: January 27, 2021, 09:49:08 am »

This has been discussed on other forums.  A big issue that has been identified is that compared to a goods train the sleeper has a significant hotel power load.
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« Reply #844 on: January 27, 2021, 01:07:39 pm »

But I think you can see why fitting batteries of a useful size to any train is a challenge, and in a locomotive it's going to be on the impossible side of very difficult for some time.

On second thoughts, that's too pessimistic. The big issue is the capacity of the batteries, and that is low even by current hybrid (road) vehicle standards. So why, could a big increase be possible soon, and if it is so limited what is it there for?

The answer to the last question must be for regenerative braking - and the batteries do replace the braking resistors in the precursor design. So it's put there to take in the kinetic energy when slowing down, and give it back again soon after. Once it's full, only friction braking is available. One implication of this is that it will not be kept full - the obvious strategy is to keep it half-full, so as to be ready for braking and for accelerating.

Future battery technology is very much a guessing game. So far, high-power applications like trains have been hard to do, and I take it that's why this one has a lower capacity/power ratio than one in a car. So a big change in that limit would alter the calculations for a hybrid, but only a very big change would make a "mains/battery" loco a go-anywhere replacement for a diesel.

This has been discussed on other forums.  A big issue that has been identified is that compared to a goods train the sleeper has a significant hotel power load.

It'll be interesting to see where this one heads over the years.  Perhaps it's a step too far for the Night Riviera and a single Class 93, although with such slack timings perhaps it could still be made to work?  25mph up the banks late evening might not be much of an issue, and I wonder what speed the current sleeper reaches up those banks?

Appreciating the difficulty of fitting batteries of any size within the design of a locomotive, is there any potential to have a 'battery pack' vehicle separate to the locomotive in the future.  I'm thinking of a similar vehicle to the power pack vehicles inserted into the Stadler Flirt bi-mode's (which is of course for diesel purposes, not batteries) but on a similar principle.  It could be semi-permanently coupled to the locomotive and be charged from it (or on depot).

A future possibility, or a no-hoper?
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« Reply #845 on: January 27, 2021, 05:54:44 pm »

Whilst a battery pack vehicle could be done, it adds cost, weight and complexity without any increase in low speed tractive effort since this is limited by adhesion and not by horsepower.

A better plan might to build a battery locomotive with traction motors and at least one driving cab.
Such a unit could be couple to an electric locomotive to give an increased low speed tractive effort (more weight on powered axles) and increased speeds up inclines due to increased total power.
The train could proceed at reduced speed on battery power alone, useful in dockyards that cant be electrified.

If coupled to a diesel locomotive, then a considerable increase in performance would be possible, at lower fuel consumption than by providing two locos. A limp home "tortoise mode" if the engine breaks would be preferable to blocking the line.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU (Diesel Multiple Unit) is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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« Reply #846 on: January 27, 2021, 10:02:38 pm »

Quote
21:45 Penzance to London Paddington due 05:04

21:45 Penzance to London Paddington due 05:04 will no longer call at St Erth.

This is due to a shortage of train crew.

Can anyone think why this applies?
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grahame
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« Reply #847 on: January 27, 2021, 10:36:24 pm »

Quote
21:45 Penzance to London Paddington due 05:04

21:45 Penzance to London Paddington due 05:04 will no longer call at St Erth.

This is due to a shortage of train crew.

Can anyone think why this applies?

Is a dispatcher needed on the platform?  But then that would not be train crew, would it ...
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TaplowGreen
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« Reply #848 on: January 28, 2021, 09:16:09 am »

Quote
21:45 Penzance to London Paddington due 05:04

21:45 Penzance to London Paddington due 05:04 will no longer call at St Erth.

This is due to a shortage of train crew.

Can anyone think why this applies?

Is a dispatcher needed on the platform?  But then that would not be train crew, would it ...

Trying again!

Is there any point in running the sleeper at the moment?

It must be virtually or totally empty

Given the criteria, it's hard to imagine any essential justification/scenario for anyone travelling from London to Penzance overnight?

Seems a very expensive way to cart air around?
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broadgage
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« Reply #849 on: January 28, 2021, 03:18:59 pm »

In my view, yes it should run.
It is an important transport link for the far south west, and there are probably a few essential workers useing it.

Closure when not busy could be the begining of closure by stealth.

Step one "closed due to the pandemic"
Step two  "Christmas closure extended into January due to little use"
Step three  "Closed for the winter season"
Step four "The closed season has been extended slightly in line with customer needs"
Step five "It is no longer economic to maintain special rolling stock for one single journey a day for less than half of the year. Our most recent passenger survey shows that only a very small percentage of our passengers use it. Most passengers prefer our improved daytime service to the older sleepers. We continue to keep the matter under review and may introduce and alternative overnight format*"

*IET (Intercity Express Train), bring your own pillow and blanket.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU (Diesel Multiple Unit) is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
TaplowGreen
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« Reply #850 on: January 28, 2021, 05:17:34 pm »

In my view, yes it should run.
It is an important transport link for the far south west, and there are probably a few essential workers useing it.

Closure when not busy could be the begining of closure by stealth.

Step one "closed due to the pandemic"
Step two  "Christmas closure extended into January due to little use"
Step three  "Closed for the winter season"
Step four "The closed season has been extended slightly in line with customer needs"
Step five "It is no longer economic to maintain special rolling stock for one single journey a day for less than half of the year. Our most recent passenger survey shows that only a very small percentage of our passengers use it. Most passengers prefer our improved daytime service to the older sleepers. We continue to keep the matter under review and may introduce and alternative overnight format*"

*IET (Intercity Express Train), bring your own pillow and blanket.

It's not economic anyway, that's why it has to be subsidised, but I'd agree it should be maintained on a social basis, as alternative links to/from the far South West are so poor.

Pragmatically however, just now it seems pretty pointless as/if it's virtually empty, and I don't see suspending it as the start of it's permanent cessation. We live in unique times and loadings/demand can be seen in that context. No-one assumes this is the status quo.

It would be interesting to hear from one of those "in the know" as to its current loadings.
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Adelante_CCT
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« Reply #851 on: January 29, 2021, 05:28:02 am »

Whomever was in the loadings this morning got turfed out at Reading anyway due to the attaching rear loco failing in Platform 2, therefore not allowing the train to continue to Paddington

Quote
21:45 Penzance to London Paddington due 05:07 will be terminated at Reading.
It will no longer call at London Paddington.
This is due to a fault on this train.
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Thatcham Crossing
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« Reply #852 on: January 29, 2021, 02:08:47 pm »

I've read elsewhere that's it's used by some south-western MP (Member of Parliament)'s?
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BBM
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« Reply #853 on: January 29, 2021, 04:15:35 pm »

I've read elsewhere that's it's used by some south-western MP (Member of Parliament)'s?

ISTR (I seem to recall/remember) seeing the Bishop of Truro using it on a TV programme a few years ago.
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stuving
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« Reply #854 on: January 30, 2021, 12:31:25 am »

Appreciating the difficulty of fitting batteries of any size within the design of a locomotive, is there any potential to have a 'battery pack' vehicle separate to the locomotive in the future.  I'm thinking of a similar vehicle to the power pack vehicles inserted into the Stadler Flirt bi-mode's (which is of course for diesel purposes, not batteries) but on a similar principle.  It could be semi-permanently coupled to the locomotive and be charged from it (or on depot).

A future possibility, or a no-hoper?

Roger Ford's e-zine for February has a section on hybrids, which covers a number of the things being tried out here. And then there's Wabtec's FLXrive:
Quote
FLXdrive is Wabtec’s newest development a battery electric freight locomotive.  Leveraging decades of application expertise, coupled with industry leading performance optimization, the hybrid consist that is being demonstrated has the capability of saving fuel and reducing emissions.

Wabtec’s FLXdrive battery electric locomotive pilot is part of a grant project with the Calfornia Air Resource Board (CARB), BNSF and the San Joaquin Valley Air Pollution Control District.  Wabtec and BNSF will begin proof-of-concept and performance testing in late 2020.  BEL is part of California Climate Investments, a statewide program that puts billions of cap-and-trade dollars to work reducing greenhouse gas emissions, strengthening the economy and improving public health and the environment— particularly in disadvantaged communities.

The specification given is confusing, but together with what's in the e-zine you get:
2400 kWh capacity
30-40 minutes discharge time - implying a power of about 4 MW
Charging only by regeneration or shore supply - but it is only a pilot
Intended to operate with two 4400 HP locomotives - this is the USA, after all
Weight (max) 430000 lb (192 t)
Powered axles 4 (out of 6)

I had assumed that the class 93 uses a lithium titanate oxide battery for its high charge/discharge rate, and it does seem that they are used in some bigger hybrid cars and in buses for that reason. Of course the separate vehicle allows a much bigger battery, allowing for a higher output power over a time Li-ion can manage.

But I did think British operators would not accept an add-on of a different kind, and even if the components were redistributed into two identical ones they would dislike running them routinely in pairs. So I can see why it's being tried in the USA - especially if there's grants to be had!
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