Great Western Main Line electrification - ongoing discussion

[whole diary]

[paul7575]

I'm probably about to ask a very dumb question (or several) - but I don't really understand this "power limited" business.

It reads to me as if there's software control on the diesel engines on the 800 and 801 class units which will limit the power that can be applied - and thus their acceleration - once they get above a certain speed. But the class 802 will be essentially the same units but with a bigger diesel fuel tank and without that limiter.

1. Do I have this right

2a. If so, why is the limiter there in the first place?
2b. If so, couldn't the limiter be removed now that the units will be running longer distances on diesel?

and

3. If I don't have it right, can someone please put me right?

An article in (IIRC^▸ (if I recall/remember/read correctly)) Modern Railways has suggested that it is technically possible to uprate the SET^▸ (Super Express Train (now IET)) performance by altering the relevant software, but the financial consortium that own the trains see it as an avoidable reliability risk, and will not permit it.

Paul

[Western Pathfinder]

I would be more than willing to explain but I fear this would end up with me rumbleing on a bit like James May late of Top Gear  up to you let me know if you think it would be usefull.

[grahame]

I would be more than willing to explain but I fear this would end up with me rumbleing on a bit like James May late of Top Gear  up to you let me know if you think it would be usefull.

You have me intrigued ... Ill take the risk please!

[dviner]

Looks like everything left to do has been scoped into CP6^▸ (Control Period 6 - The five year period between 2019 and 2024).

In a way this is unbelievable, a nightmare scenario, I remember when the ECML^▸ (East Coast Main Line) was electrified in the 1980s everything seemed to happen quickly and the total cost was under budget. I suspect, although I do not know, that the GW^▸ (Great Western) scheme has been massively over-engineered. My suspicion is that our old friend Health & Safety is probably at the root of it all.

Let's put this thought forward:

The GW scheme hasn't been massively over-engineered.

The GW scheme has been engineered on a basis of building something that will work, work well, and that can be rolled out across the rest of the electrified railway network.

What would have been interesting was whether productivity had been increasing. I doubt it would now, as it's been knifed.

[Chris from Nailsea]

Meanwhile, in the interests of clarity and continuity, I have merged a couple of topics here - as they both relate to the electrification of the Greater Western route, and the delays now apparent.

May I also offer my thanks here to everyone who has contributed here already to such a lively discussion, on such a live subject.  

[GBM]

.............manana, manana, manana.............

As it's also impacting on the far West, we would say 'drekly'

[TaplowGreen]

.............manana, manana, manana.............

As it's also impacting on the far West, we would say 'drekly'

..........and speaking as a Janner, it certainly isn't a "Proper Job" 

[Western Pathfinder]

I would be more than willing to explain but I fear this would end up with me rumbleing on a bit like James May late of Top Gear  up to you let me know if you think it would be usefull.

You have me intrigued ... Ill take the risk please!

Ok then   As Paul mentioned above it is possible to play around with the engine management software  but in doing so you run the risk that the overall performance and length of service that could be expected from the power unit will be greatly reduced ,this of course will lead to more down time and increased servicing costs as well as a reduction in fuel economy and an increase in exhaust emissions

As to the Question of the Limiter issue
Most if not all diesel engines in a rail application are governed as to the maximum amount of speed that they can run at
This is for reasons of efficiency as unlike the engine in your car or van the amount of speed that the engine is developing is not directly related to the speed at which you are traveling at
Yes I know that the trains would appear to accelerate with a corresponding rise in engine speed but it's only from a state where the power unit is at idle for reasons of economy and also to save the passengers from the noise of the engine reving when not needing generate full power for traction purposes

So simply put a loco or a power car that is diesel electric is really a portable self propelled generating unit
Hope this is of some use and answers one or two of your points  Grahame

Was hoping to get this posted last night
But you know what they say about a friend in need  and when they turn up unannounced !.....

[ChrisB]

In that diagram upthread, the pacers are still to be decommissioned, just a year later than was planned

[stuving]

Ok then   As Paul mentioned above it is possible to play around with the engine management software  but in doing so you run the risk that the overall performance and length of service that could be expected from the power unit will be greatly reduced ,this of course will lead to more down time and increased servicing costs as well as a reduction in fuel economy and an increase in exhaust emissions

I'm not convinced by that - at least not by the "greatly". Almost identical trains will be operated by GWR^▸ (Great Western Railway) with the same engine/alternator package but at full power. On the (admittedly rather sketchy) information available, the MTU^▸ (Motor Traction Unit) type 12V 1600 R80L engine and the TSA^▸ (Ticketing and Settlement Agreement.) (Traktioneysteme Austria) TG 59-43-4 induction alternators are both rated at 700 kW, and are identical in both cases. While in the 802s they will run up to full power, in 800s they will be limited to 560 kW. In both cases that limit is purely a matter of the operating regime defined in software - 800s will have 700 kW available if a generator package fails, and I guess that 802s may be set up to minimise full power running in some way.

Presumably Hitachi don't think the engines in 802s will disintegrate after a couple of years, and their financial backers Eversholt Rail presumably don't think the risk is such an issue. So I imagine Paul is right, it's the cumbersome nature of the funding for IEP^▸ (Intercity Express Program / Project.) that makes it difficult to negotiate the reuprating - which may even be a single line in the software!

The one thing about higher-power running that isn't "only software" is the reduction in range between refuelling, given the smaller fuel tanks in 800s. That might be a big issue, or it could be nothing, you'd need some rather specific inside information to know.

[grahame]

I would be more than willing to explain but I fear this would end up with me rumbleing on a bit like James May late of Top Gear  up to you let me know if you think it would be usefull.

You have me intrigued ... Ill take the risk please!

Ok then   ...

Hugely appreciate the answer - thanks.     And the others too on this discussion.  I have often wondered what was "really" involved and I think we now have a range of considerations / ramifications (shorter engine life, more fuel used so need for more frequent re-tanking which may effect diagrams, contractual issues to sort out) ... good to know.  Oh - and it seems that it's unlikely that the change would create an unreliable train.   Whether it's work it for acceleration out of Bath / Bristol is another matter ...

[ChrisB]

Unreliable as in out of service more often/for longer, I think....

[grahame]

Presumably Hitachi don't think the engines in 802s will disintegrate after a couple of years, and their financial backers Eversholt Rail presumably don't think the risk is such an issue. So I imagine Paul is right, it's the cumbersome nature of the funding for IEP^▸ (Intercity Express Program / Project.) that makes it difficult to negotiate the reuprating - which may even be a single line in the software!

Probably just a configuration file then - not even a single software line to change.  Hopefully Hitachi programmers don't hard code too many constants ...

[ChrisB]

Hitachi will charge a lot of money to lift these restrictors

[broadgage]

So to summarise, the new trains will be slower than the old ones when on diesel power which is a large part of the mileage. To increase the performance may be very challenging from a contractual point of view and will increase costs and probably decrease reliability.
Presumably fares will increase* to cover these extra costs, and more half length trains will appear to cover for any extra breakdowns, and of course for extra trips to fuelling points.

The noise and vibration from the underfloor engines will presumably increase if run at a higher output, and will certainly be present for a greater part of the journey than was anticipated.

I seem to recall Mark Hopwood stating that passengers did not want underfloor engines on intercity trains. When I cynicly pointed out that underfloor engines was exactly what were getting, advocates of the new trains implied that this did not much matter because the trains would be mainly run on electric power.

*It has been stated that fares wont rise to pay for the new trains. I expect some substantial hidden fare rises to pay the extra and still rising costs.

The whole project is rapidly turning into a huge fiasco.