Bi-modes using diesel under the wires

[gabrielhj07]

I’ve just seen 1B46 Paddington - Swansea pull into Reading in diesel mode. Why would this be? It’s not like the ECML around Berwick where the power supply can’t cope, and it’s a 10 car set so has plenty of pantographs if one fails.

 

[Snow1964]

Unless the power was off, not an obvious reason.

I vaguely remember a new power feeder (related to the National Grid switch station at Bramley) was due to come online about now, perhaps it was related to commissioning or testing this.

 

[gabrielhj07]

I did wonder about the power being down, but 345s & 387s were about.

 

[1Q18]

It’s possible that one or other unit currently has a diesel-only restriction.

 

[gabrielhj07]

It’s possible that one or other unit currently has a diesel-only restriction.

How would such a restriction come about?

 

[1Q18]

How would such a restriction come about?

It would be imposed by Hitachi if there was a fault preventing the unit from running in electric mode.

 

[gabrielhj07]

Sounds pragmatic. What sort of failure might lead to this restriction? Sorry to keep asking new questions, it’s interesting!

 

[Snow1964]

Sounds pragmatic. What sort of failure might lead to this restriction? Sorry to keep asking new questions, it’s interesting!

I was wondering that too, it uses electric motors, so more a case of restricting where the electricity is supplied from.

But as a follow up question, why would it need to be pressed into service on the thinner Sunday service when fewer units needed.

 

[QSK19]

I’ve seen a couple of videos of HT Paragons using St Pancras as a diversionary station. On both occasions, it was running on diesel mode. Would it be to do with ensuring that the electrical supply isn’t overloaded (as in, the Paragon would be one more “mouth to feed” so to speak)?

 

[popeter45]

Sounds pragmatic. What sort of failure might lead to this restriction? Sorry to keep asking new questions, it’s interesting!

Faulty pantograph or transformer are 2 ideas I can think of?

 

[swt_passenger]

I’ve seen a couple of videos of HT Paragons using St Pancras as a diversionary station. On both occasions, it was running on diesel mode. Would it be to do with ensuring that the electrical supply isn’t overloaded (as in, the Paragon would be one more “mouth to feed” so to speak)?

I think there’s a 100 mph speed restriction for the MML OHLE, so it may be to allow them to run at the same speed as 222s.

 

[QSK19]

I think there’s a 100 mph speed restriction for the MML OHLE, so it may be to allow them to run at the same speed as 222s.

Yep indeed true; however I was under the impression that the line speed only exceeds 100mph north of Cricklewood? If this is true, they could theoretically put the pan up from there to STP.

Having said that, given how infrequently they go to STP, the simplest solution would be to run on diesel regardless so that issues around OHLE speed limits, electrical supply, etc, are negated.

 

[hexagon789]

Yep indeed true; however I was under the impression that the line speed only exceeds 100mph north of Cricklewood? If this is true, they could theoretically put the pan up from there to STP.

Having said that, given how infrequently they go to STP, the simplest solution would be to run on diesel regardless so that issues around OHLE speed limits, electrical supply, etc, are negated.

As I understand it, that is precisely what will happen with the 810s - electric to Cricklewood (max 95mph), then switch to diesel to accelerate to 110 and higher where permitted.

 

[swt_passenger]

Yep indeed true; however I was under the impression that the line speed only exceeds 100mph north of Cricklewood? If this is true, they could theoretically put the pan up from there to STP.

It’s only going to be about 5 miles so I suspect probably not worth bothering, especially if they can’t pan up on the move.

 

[hexagon789]

It’s only going to be about 5 miles so I suspect probably not worth bothering, especially if they can’t pan up on the move.

Perhaps they won't then, but the impression I had from various interviews and articles relating to the 810s was that they would use OLE to Cricklewood.

 

[swt_passenger]

Perhaps they won't then, but the impression I had from various interviews and articles relating to the 810s was that they would use OLE to Cricklewood.

Sorry I was only referring there to Hull trains on diversion, I wasn’t thinking about EMR 810s in future.

But for EMR isn’t it supposed to be only a transitional thing until the OHLE is altered anyway?

 

[FGW_DID]

I’ve just seen 1B46 Paddington - Swansea pull into Reading in diesel mode. Why would this be? It’s not like the ECML around Berwick where the power supply can’t cope, and it’s a 10 car set so has plenty of pantographs if one fails.

According to RTT the service was formed of 800020 & 800017:

Realtime Trains | 1B46 1443 London Paddington to Swansea | 19/03/2023

Real-time train running information for 1B46 1443 departure from London Paddington to Swansea on 19/03/2023. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

800020 currently has a diesel only restriction.

 

[Jozhua]

Surprising that the 810s will be running in Diesel under the wires still for much of the route anyway! Any idea when the OLE upgrades are due to happen? Or is it just the case of slow upgrades where assets are becoming life expired?

As I understand it, that is precisely what will happen with the 810s - electric to Cricklewood (max 95mph), then switch to diesel to accelerate to 110 and higher where permitted.

So does this mean the 360s are limited to 100mph then Vs 110? I've had a few times where my 222 service has been following a connect into St Pancras and got somewhat delayed due to it.

It’s only going to be about 5 miles so I suspect probably not worth bothering, especially if they can’t pan up on the move.

The big thing would be reducing noise/pollution within St Pancras and central London I'd guess, so maybe they'll do it mostly for that.

 

[plugwash]

Generally modern electric traction uses an AC->DC->AC system, where AC from the OHLE or generators is converted to DC and back to AC for the motors. This may seem strange, but it allows 3 phase motors to be used on a trains supplied with single phase AC and allows the motor frequency to be varied to suit the current speed and power demand.

From what I can find online, It seems on the 80x that the supply converters (the parts that turn AC from the generators/overhead to DC) are shared between both operating modes. So It would presumablly be a fault related to the pantograph, transformer or some item of switchgear or monitoring equipment that would preclude operation off OHLE while allowing operation off diesel.

 

[gabrielhj07]

A few more at Reading today: 802007 arrived on diesel from Paddington then switched to electric in the platform. 800009 on diesel passing non-stop.

 

[dk1]

I have occasionally run on diesel Ely-Cambridge North but apart from one time because of OHL speed restrictions and I wanted to be right time it’s been because I forgot to change the power over at Ely lol.

 

[Warrior2852]

A few weeks ago I saw something interesting with a TPE 802 that I got between Leeds and Durham (on a service to Newcastle). It was in diesel mode at Leeds when I got on it as expected, switched to electric at York, again as expected, but then when I got off at Durham I turned around and saw the pantograph going down, just as the engine turned on, and then it left Durham in diesel mode, despite the rest of the way to Newcastle still being electric, not sure why this happened as it had been electric York to Durham, and it wouldn't have been taking the Sunderland divert or anything as that's at Northallerton.

 

[snowball]

A few weeks ago I saw something interesting with a TPE 802 that I got between Leeds and Durham (on a service to Newcastle). It was in diesel mode at Leeds when I got on it as expected, switched to electric at York, again as expected, but then when I got off at Durham I turned around and saw the pantograph going down, just as the engine turned on, and then it left Durham in diesel mode, despite the rest of the way to Newcastle still being electric, not sure why this happened as it had been electric York to Durham, and it wouldn't have been taking the Sunderland divert or anything as that's at Northallerton.

As previously discussed in other threads, some TPE trains run in diesel mode on parts of the northern ECML because the power supply, designed back in the 1980s, does not currently have the capacity to allow every electric-capable train to run in electric mode throughout. There is a programme to upgrade the feeder stations. Though I admit I thought the problem was mainly north of Newcastle.

 

[Ken H]

As previously discussed in other threads, some TPE trains run in diesel mode on parts of the northern ECML because the power supply, designed back in the 1980s, does not currently have the capacity to allow every electric-capable train to run in electric mode throughout. There is a programme to upgrade the feeder stations. Though I admit I thought the problem was mainly north of Newcastle.

Maybe the National Grid was in trouble and asked the railway to limit use. Might be worth looking at the history on https://www.gridwatch.templar.co.uk/ and see if there was a issue that day. But that wont tell you about a missing generating asset.
Link goes to a graphical display of current UK electricity demand and supply by generation type, together with connectors to foreign electricity networks.