Are DRS 88's and 68's normally double headed?

[SarahSanderson]

Today's 4Z27 0546 Mossend Down Yard to Daventry Int Rft Recep Fl was double headed by 88002 "Prometheus" and 68016 "Fearless". Is it normal to combine a 68 with an 88? I notice the working went via the ECML so I am assuming there may be an unwired section somewhere along the line. The 68 was definitely giving power when it left Stechford and the images show the 88 had the pantograph up.

I apologise if this is normal, just something I have never seen before.

Small images attached - full size at link below for those who are interested.

Sarah Sanderson

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[Bald Rick]

It was off the wires from Doncaster to Walsall, so yes rather a large gap!

 

[themiller]

Yes, there would be an unwired section going via ECML. The 68 would be needed to keep the speed up on that section. The 88 could move the train but at severely reduced speed thus eating up paths. The 68 may have been assisting the 88 so that the engine was at operating temperature when required.

 

[SarahSanderson]

Thank you Bald Rick! I am not too au fait with where the wires end these days. It was just weird to see an 88 crawl round the curve from Aston but hearing a diesel!!

 

[Bertie the bus]

I think 68 + 88 is common when DRS intermodals are routed via the ECML. At other times it has occurred but isn't common.

 

[SarahSanderson]

Yes, there would be an unwired section going via ECML. The 68 would be needed to keep the speed up on that section. The 88 could move the train but at severely reduced speed thus eating up paths. The 68 may have been assisting the 88 so that the engine was at operating temperature when required.

Thank you. All adds to my knowledge of these things!

 

[Bevan Price]

If a Class 88 is unavailable, a pair of 66s or 68s is used when the Tesco trains (Daventry / Mossend) go via Shap & Beattock on their normal route via the West Coast Main Line.

 

[D365]

The 68 may have been assisting the 88 so that the engine was at operating temperature when required.

Does the 88 switch to diesel mode when the 68 is started?

 

[172007]

As I believe 88 has to lead under the wires as for some reason the 68's were never provided with a pantograph down button otherwise they are multiple working capable.

 

[SarahSanderson]

As I believe 88 has to lead under the wires as for some reason the 68's were never provided with a pantograph down button otherwise they are multiple working capable.

The 88 was pantograph up and the 68 was providing power as the first image shows - and it certainly sounded that way. I assumed if the 88 was in diesel mode then the pantograph would be down. Maybe my assumption is wayward!

 

[themiller]

If I remember correctly, when a 68 and a 88 are working a train, any combination is possible including the 88 drawing power from the overhead at the same time as using its diesel engine. The 88 can also use this arrangement when coupled to a 68 which is also powering. As an aside, the 93s will also able to use all sources in boost mode if I read the description correctly.

 

[D365]

Really? I’m surprised that an 88 would be set up to dual-feed the traction equipment.

 

[Richard Scott]

Really? I’m surprised that an 88 would be set up to dual-feed the traction equipment.

I don't think dual feed would be a possibility. You'd need to match input frequency to motors exactly from both sources. What would the point be as diesel engine brings little to the party on this one?

 

[43096]

I don't think dual feed would be a possibility. You'd need to match input frequency to motors exactly from both sources.

Not if you feed into the DC link?

What would the point be as diesel engine brings little to the party on this one?

But for the 93s that will have batteries and diesel engines, they will have to feed both into the traction supply at the same time.

 

[D365]

I don't think dual feed would be a possibility. You'd need to match input frequency to motors exactly from both sources. What would the point be as diesel engine brings little to the party on this one?

This was going to be my follow-up question. Surely no point having that facility on an 88 where the dual-power architecture is more akin to a 769.

 

[Richard Scott]

Not if you feed into the DC link?

But for the 93s that will have batteries and diesel engines, they will have to feed both into the traction supply at the same time.

That's easy to do as input both as DC supplies and then use inverters. True could be done for an 88 as didn't think there, both probably rectified to DC first!

 

[D6130]

I saw a similar combination passing through York yesterday evening (Sunday 19th) at the head of 4Z48, 11 59 Mossend-Daventry....but, unfortunately, I was just leaving the York Tap and didn't manage to see the loco numbers, let alone take a photo or video.