Hull Trains - OHL to Diesel Changeover

[swt_passenger]

It may also be the wiring in the Temple Hirst area can't take changeover on the move. On GWR where it takes place there is higher tensioning so the process of raising / lowering the pantograph doesn't bring down the wires.

Somewhere in the GW electrification thread, (or maybe the original class 800 thread?), it was explained that is not actually the case. NR defined certain areas for changeover to happen so that they could be more closely monitored for wear, but the tension is the same everywhere...

 

[Starmill]

I imagine a key reason for the need for software to avoid 'cold starts' was that originally the train's maintainer would have suffered the financial losses if the engines were degraded excessively by their inadequate pre-heating, while their operator gained a small performance benefit.

Rodger Ford wrote an article prior to the 80x introduction about the inadequate attention that had been paid to the problem of pre-heating the diesel power packs, and the costs involved in solving the problem.

 

[SouthEastBuses]

HT and TPE could just be doing this at stations for a period until they are confident that drivers are remembering to do the changeover (given that it's not something they'll have been doing until fairly recently) - given the potential costs if a train were to try running beyond the wires without having turned the diesel engines on?

I don't know if other TOCs were changing power "on the move" (rather than when sat at stations), but I could see sense in taking precautions when introducing new technology.

GWR does that on the London-Worcester/Great Malvern route. Between Reading and Oxford, what they do is that they run in electric mode until the junction at Didcot Parkway (not actually stopping at the station but passing nearby), then on the move around Didcot Parkway they change from electric to diesel (and viceversa) and they continue to Oxford and eventually Worcester and Great Malvern.

 

[43066]

I'm sure that they would stop whilst still on the wires, but it's the stopping at all that irks me. I don't know how many high speed transitions there are, but delaying the train because the engine is cold with consequent risks of snowballing delay later down the line just doesn't seem the right thing to do. It does feel a bit horse before cart here, the railway is run for the passenger's benefit, not for Hitachi's convenience

It sounds like that’s only going to be necessary in the event of something out of course happening, though. In which case it may well be more prudent to stop and work out what the problem is while still under the wires, rather than risk coasting and stranding off juice if the engines cannot be started due a more serious fault than low temperature.

 

[alangla]

Hope this is the right place to ask but do class 80x units have electric engine pre-heating and if so, does it run all the time or only in preparation for a change? I realise that barring a wires down incident there’s little point in preheating a unit that’s spending the day plodding between Kings X and Edinburgh or Leeds but the cost of doing so would surely be marginal

 

[800001]

Hope this is the right place to ask but do class 80x units have electric engine pre-heating and if so, does it run all the time or only in preparation for a change? I realise that barring a wires down incident there’s little point in preheating a unit that’s spending the day plodding between Kings X and Edinburgh or Leeds but the cost of doing so would surely be marginal

Engines are not turned on until needed

 

[DidcotDickie]

Somewhere in the GW electrification thread, (or maybe the original class 800 thread?), it was explained that is not actually the case. NR defined certain areas for changeover to happen so that they could be more closely monitored for wear, but the tension is the same everywhere...

This is correct and has been pointed out by myself and others elsewhere. The 'higher tension' for power changeover is a myth that seemingly refuses to die The wire tension on the Series 1 OLE on the GWML is higher than used elsewhere on NR but is the same throughout.

 

[dk1]

I’ve been told that diesel engines on 8XXs need to be warmed up by running them for a period before the changeover can occur (when going from electric to diesel obviously). Any truth in this?

We dont bother with 755s. Whether (or weather) we will be asked to during sub zero temperatures remains to be seen.

 

[43096]

Engines are not turned on until needed

Which doesn’t answer the question that was asked about pre-heating.

 

[43066]

Hope this is the right place to ask but do class 80x units have electric engine pre-heating and if so, does it run all the time or only in preparation for a change? I realise that barring a wires down incident there’s little point in preheating a unit that’s spending the day plodding between Kings X and Edinburgh or Leeds but the cost of doing so would surely be marginal

Several posts immediately above are discussing the need for 80Xs engines to be run to pre heat them!

 

[Stathern Jc]

Slightly off the main subject of changeover points and the planned procedure.

If it's necessary to coast or pause while engines warm up as indicated in earlier comments, what's the situation with unanticipated power outages?
It sounds like an undesirable extra delay if the 8xxs have to sit waiting for the engines warm up. Can they "crawl" on lower output until sufficiently warmed up? Or is this a tolerated exception?

Without having any information on this I had assumed that some means of preheating would have been included such as during overnight connections to shore supplies, and that if so it could have also been used when under the wires in readiness for diesel running. It appears not.

 

[PennineSuperb]

Class 80X Generating Units (GU's) need the engine coolant to be at least 45' before pressing 'Engine Start'. (Instructions from the engine manufacturer to decrease wear on components and give longer engine life - the engines even send information to the manufacturer if they are started without pre heat).
Pre heating is completed via the TMS at locations recommended to Drivers. (For example at Tollerton when trains are routed to Leeds after York, this gives 10 minutes for pre heating.) Automatic Power Change Over (APCO) is fitted to the TPE 802's but at the minute is isolated. Company instruction is also not to raise the pantograph on the move.

 

[Philip Phlopp]

Slightly off the main subject of changeover points and the planned procedure.

If it's necessary to coast or pause while engines warm up as indicated in earlier comments, what's the situation with unanticipated power outages?
It sounds like an undesirable extra delay if the 8xxs have to sit waiting for the engines warm up. Can they "crawl" on lower output until sufficiently warmed up? Or is this a tolerated exception?

Without having any information on this I had assumed that some means of preheating would have been included such as during overnight connections to shore supplies, and that if so it could have also been used when under the wires in readiness for diesel running. It appears not.

I don't know if this is still how it's done, but cold starting MTU engines used to add a 'penalty' number of hours to the engine hours, so starting an engine cold and running for one hour would add, say, six hours total to the engine hours - one hour for the actual hour run, plus a penalty of five hours. The net effect was it resulted in maintenance intervals shrinking considerably. This particularly impacted the MTU fitted HST powercars in the early days, which resulted in lots of instructions to keep them on a shore supply or keep them running if a shore supply wasn't available.

 

[SouthEastBuses]

Also, for the London Bristol route via Bath spa, I seem to have noticed that the electrification from Royal wootton Bassett continues all the way right until the approach to Chippenham station. So is the transition from electric to diesel (and vice versa) on the move done on approach to Chippenham then? (Where the wires end)

 

[Mag_seven]

So is the transition from electric to diesel (and vice versa) on the move done on approach to Chippenham then? (Where the wires end)

It is.

 

[SouthEastBuses]

It is.

Ok thanks. Hopefully the electrification will be extended to Bristol Temple Meads in a few years, as it was originally planned.

 

[43096]

I don't know if this is still how it's done, but cold starting MTU engines used to add a 'penalty' number of hours to the engine hours, so starting an engine cold and running for one hour would add, say, six hours total to the engine hours - one hour for the actual hour run, plus a penalty of five hours. The net effect was it resulted in maintenance intervals shrinking considerably. This particularly impacted the MTU fitted HST powercars in the early days, which resulted in lots of instructions to keep them on a shore supply or keep them running if a shore supply wasn't available.

The statement at the time on the MTU 4000s was that a cold start added 100hrs onto the MDEC (engine management system) engine hours.

 

[alangla]

Class 80X Generating Units (GU's) need the engine coolant to be at least 45' before pressing 'Engine Start'. (Instructions from the engine manufacturer to decrease wear on components and give longer engine life - the engines even send information to the manufacturer if they are started without pre heat).
Pre heating is completed via the TMS at locations recommended to Drivers. (For example at Tollerton when trains are routed to Leeds after York, this gives 10 minutes for pre heating.) Automatic Power Change Over (APCO) is fitted to the TPE 802's but at the minute is isolated. Company instruction is also not to raise the pantograph on the move.
View attachment 85086

Thank you! This is the answer I was looking for & thanks for posting all the details. So it seems they *do* have electric pre-heat, but it's activated by the TMS rather than being on continually.