Night Riviera - merged posts, ongoing discussion

[whole diary]

[broadgage]

80 KWH from batteries is not very much, is this limited battery power intended to move a train on its own ? Or is it intended to supplement the diesel engine. The later I suspect.

900 KW from diesel is useful, 900Kw  from diesel plus 400 Kw from batteries is very useful, even if the battery contribution is only for a few minutes. An 80 KWH battery if discharged at the stated 400 KW will only last about 12 minutes.
900 Kw on level track and  1,300Kw up banks for example, 1,300 KW when accelerating away from stops is also helpful.

Hopefully when in electric mode, the battery can supply ETS^▸ (Electric Train Supply) during brief gaps in contact with the overhead.

[IndustryInsider]

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?

[stuving]

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

[stuving]

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.

[TaplowGreen]

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?

[eXPassenger]

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.

[IndustryInsider]

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?

[broadgage]

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.

[bobm]

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?

[grahame]

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 ...

[TaplowGreen]

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?

[broadgage]

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.

[TaplowGreen]

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.

[Adelante_CCT]

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

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.

[Thatcham Crossing]

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