Push Pull vs Hybrid

[Matt P]

I watched a recent video online recently about the Southern region's 4TC sets and I wondered why the concept never took off elsewhere on the network where through services traversed electrified and non-electrified routes. Cross country in particular seems to been a potentially ideal group of services where either a non-powered train set with control cars/DVTs at both ends or an EMU could operate with a locomotive being taken on/off at appropriate sections - I appreciate for the non-powered train set this would mean taking both diesel and electric locomotives off, but BR and pre-Voyager, Virgin, did this anyway for some services.

Cross country runs a lot of route mileage under the wires but currently uses diesel throughout. More specifically to the post though, we have also seen the introduction of hybrid trains on a number of routes in recent years.

Over the 20-30 year lifespan on rolling stock is really cheaper for a train to be carrying round a diesel engines so it can run off-wire. Whilst the obvious solution is more electrification, which ultimately comes a cropper due to costs, would it not be more efficient and cost effective to have a pure EMU that can work in push/pull mode with a diesel locomotive that is used for those sections of the service that run off wire?

I suspect the answer is probably no, at least not in terms of the up front capital cost of having to buy a fleet of locomotives and a fleet of EMUs, where as hybrids allow for the purchase on a single fleet of trains. But when long term operating costs are factored in, would the push pull option have any advantages?

 

[30907]

The problem with XC is that it is largely unwired, so you would be detaching the diesel for relatively short sections (York-Newcastle/W Mids-Manchester). There would have been a better case (and I've seen it argued) for the ECML north of Edinburgh.

But short or long you are adding staffing costs and inefficiencies at each loco change, which is why BR Cross Country started running diesels under the wires instead, a trend that has been followed in other parts of Europe for the same reason.

 

[MattRat]

And XC can't just order some Bi mode IETs because?

 

[D365]

I suspect the answer is probably no, at least not in terms of the up front capital cost of having to buy a fleet of locomotives and a fleet of EMUs, where as hybrids allow for the purchase on a single fleet of trains. But when long term operating costs are factored in, would the push pull option have any advantages?

Bi-mode rolling stock eliminates shunting movements and thereby the risk of delays when changing over. Either from defective locomotives (mechanically or electrically), failure of coupling/multiple working, or staffing issues.

 

[Darandio]

And XC can't just order some Bi mode IETs because?

Because the government won't allow them to do it.

 

[MattRat]

Because the government won't allow them to do it.

And why would they allow OPs proposal? Since it is more complicated so likely more expensive.

 

[30907]

Because the government won't allow them to do it.

And when Government finally allows XC to increase capacity, there are plenty of 22x going begging that are well short of being life expired.

 

[JonathanH]

One thing about Bournemouth is that the track layout was designed around the 33+TC+REP arrangement. While Coventry and York could possibly be made to work, there probably aren't too many other places where lopping locomotives off formations would really work with modern track plans. It makes for another source of delay as well.

 

[RobShipway]

And when Government finally allows XC to increase capacity, there are plenty of 22x going begging that are well short of being life expired.

As has been said on a few threads, you could have the some the 4 7 car class 222's, plus 4 of the 5 car class 220/0 units replace the XC IC125 fleet.

The 34 class 220 units could replace the class 170 units and the Avanti class 221 units join XC to work alongside their existing class 221 fleet to enable 10 car trains.

Otherwise, I can see the class 222 fleet going to Grand Central to enable future possible services, such as Kings Cross - Cleethorpes.

One thing about Bournemouth is that the track layout was designed around the 33+TC+REP arrangement. While Coventry and York could possibly be made to work, there probably aren't too many other places where lopping locomotives off formations would really work with modern track plans. It makes for another source of delay as well.

Which is why diesel trains is used at the moment by XC and other TOC's, with bi or tri - mode trains possibly used in the long term future. Short term though they are likely to use existing diesel stock, that is not as yet life expired such as the class 175, 180 and 22x fleets.

 

[D365]

The 34 class 220 units could replace the class 170 units…

How many times does it have to be said that this won’t happen.

 

[RobShipway]

How many times does it have to be said that this won’t happen.

It is not the wildest ideas within the speculation forum, especially if you read the Future of class 379 thread about class 707 units returning to SWR and the cancelling of the building of the 701 units which is about half way through the building of the 701/0 units I believe.

 

[2192]

The 33+TC+TC+4Rep scheme worked well, except that it was difficult to shorten a train at the London end. 12 cars were needed in the morning rush hour, but you were stuck with that length until you got back to Bournemouth, and the traffic on offer didn't need it. It would have caused too much congestion at Waterloo to pop a shunting engine on the end to detatch four trailer cars for the carriage sidings. So a lot of fresh air was carried until the evening rush hour.

 

[zwk500]

Over the 20-30 year lifespan on rolling stock is really cheaper for a train to be carrying round a diesel engines so it can run off-wire. Whilst the obvious solution is more electrification, which ultimately comes a cropper due to costs, would it not be more efficient and cost effective to have a pure EMU that can work in push/pull mode with a diesel locomotive that is used for those sections of the service that run off wire?

Dropping a loco on and off is marginally more fuel efficient but much less operationally and staff efficient than DMU operation. Bi-Mode operation is marginally less fuel efficient than EMU operation but far more fuel, staff and operationally efficient than DMU or loco drags.

I suspect the answer is probably no, at least not in terms of the up front capital cost of having to buy a fleet of locomotives and a fleet of EMUs, where as hybrids allow for the purchase on a single fleet of trains. But when long term operating costs are factored in, would the push pull option have any advantages?

No, because you need to include infrastructure at stations to allow the shunting. You also need the same number of EMUs as you wold DMU/B-MMUs, plus the additional locos. You also need more staff, or at least more training for staff as it's 2 types of train and additional moves.

There would have been a better case (and I've seen it argued) for the ECML north of Edinburgh.

I wouldn't have been surprised if it was considered, but the presence of the HST sets anyway and a desire to maximise utilisation on the Class 91s by operating the IC225 as effectively fixed-formation would presumably have put paid to it. Dropping the diesel straight onto the 91 would have been easy enough but would then tie a 91 up for several hours. Swapping the locos outright would have required substantial platform capacity at Edinburgh, with the Diesel standing on 19/20, 91 pulls the set into 1/2, detaches and moves to the free west end platform, then the diesel backs on before departing around the 91.

Virgin used to do it with 57s + 390s into Voyager days - 5-cars would run to Holyhead in the week, but a 9-car Pendo would be used at weekends IIRC. It stopped when there was a coupling failure and Alstom said they should only be hauled for rescue purposes.

 

[Energy]

And XC can't just order some Bi mode IETs because?

XC will first need quotes from Hitachi and other suppliers for these new trains (supposedly not that cheap anymore). They can then write a business case to the DfT showing how they can justify these new trains, either by reduced operating cost or additional passengers. The DfT would likely want a comparison to leasing spare 221s and if the business case is positive new trains for XC could be approved.

They could also try and justify more subsidy though that's realistically not going to happen right now.

As has been said on a few threads, you could have the some the 4 7 car class 222's, plus 4 of the 5 car class 220/0 units replace the XC IC125 fleet.

The 34 class 220 units could replace the class 170 units and the Avanti class 221 units join XC to work alongside their existing class 221 fleet to enable 10 car trains.

How do these numbers add up? +20 221s to voyager operation, take away 34? 220s aren't a good fit for turbostar routes, they have the wrong door positions and lower capacity.

 

[MattRat]

XC will first need quotes from Hitachi and other suppliers for these new trains (supposedly not that cheap anymore). They can then write a business case to the DfT showing how they can justify these new trains, either by reduced operating cost or additional passengers. The DfT would likely want a comparison to leasing spare 221s and if the business case is positive new trains for XC could be approved.

They could also try and justify more subsidy though that's realistically not going to happen right now.

And the same will happen for OPs proposal, with the added fact It's more effort and likely more expensive than IETs. If OPs proposal was ever considered viable, so would IETs.

 

[RobShipway]

XC will first need quotes from Hitachi and other suppliers for these new trains (supposedly not that cheap anymore). They can then write a business case to the DfT showing how they can justify these new trains, either by reduced operating cost or additional passengers. The DfT would likely want a comparison to leasing spare 221s and if the business case is positive new trains for XC could be approved.

They could also try and justify more subsidy though that's realistically not going to happen right now.

How do these numbers add up? +20 221s to voyager operation, take away 34? 220s aren't a good fit for turbostar routes, they have the wrong door positions and lower capacity.

Trains with the wrong door positions have been used before now.

Like other TOC's are having to do, I think that XC can run the timetabled services with less trains depending on what they receive from both the EMR class 222's being released and the Avanti West Coast 221 fleet being released.

 

[Energy]

And the same will happen for OPs proposal, with the added fact It's more effort and likely more expensive than IETs. If OPs proposal was ever considered viable, so would IETs.

Indeed. XC also have a tendency to get delayed due to running on so many different parts of the network, adding loco movements on top wouldn't help