Class 67s at 125mph

[Mordac]

So I know that 67s official max speed is 125mph, however I've very often seen spekticism expressed about whether they can actually do this speed in practice. What's the reason for this? Have they ever reached that speed in service? I know they did in tests...

 

[Polarbear]

I don't think they've ever done 125mph in service. I'm sure two of the reasons cited for this are;

• The axle loading & consequent access charges
• The fuel consumption at that speed

I'm sure someone will be able to confirm this, or provide a more detailed picture.

 

[Darandio]

Wasn't there something with brakes as well? Full confidence they could do 125mph, not so much confidence they could stop?

I might be wrong, but i'm sure it was mentioned somewhere.

 

[LNW-GW Joint]

So I know that 67s official max speed is 125mph, however I've very often seen spekticism expressed about whether they can actually do this speed in practice. What's the reason for this? Have they ever reached that speed in service? I know they did in tests...

The Sectional Appendices indicate that there are restrictions to 100mph over some structures, and to 110mph on the GW Route west of Reading (because of signal spacing).
But it doesn't explicitly say it is allowed 125mph or not elsewhere.

 

[CosherB]

No doubt DBC will shy away of it because of the cost, but why don't they re-gear the 67s to 100mph max, to improve lower speed performance? I'm sure someone can also provide technical reasons why it may not be practical.

 

[TimboM]

No doubt DBC will shy away of it because of the cost, but why don't they re-gear the 67s to 100mph max, to improve lower speed performance? I'm sure someone can also provide technical reasons why it may not be practical.

I suspect the incremental benefits of the re-gearing vs just not running then above c.100 mph (as is the case now) wouldn't justify the cost. The 68s have also largely taken over the 67s mixed-use 100mph loco market and are more efficient, reliable, comfortable for drivers etc. I doubt a re-gearing would be enough to claw much if any of this business back from the 68s/DRS.

Agree would be interesting from a practical point of view how feasible it is though.

 

[SpacePhoenix]

Would they be any good as "Thunderbird" locos if they were to be fitted with a retractable dellner coupling?

 

[dgl]

Would they be any good as "Thunderbird" locos if they were to be fitted with a retractable dellner coupling?

I believe that they are used on the ECML for just that purpose although we are dealing with generally standard locomotive hauled stock so I does not need special coupling adaptors Etc.

I do believe that if it ever does have to rescue a Mk4 set speed is something it gets to quite slowly and 125mph? forget about it.

 

[D1009]

According to Wikipedia one reached 230 km/h (143 mph) on test in Spain.

When the class was ordered by EWS, there was a hope of retaining regular mail traffic using 4 coach formations of vans cleared for 125 mph running, and for this reason they were equipped with enhanced braking to overcome the speed restrictions on loco hauled trains formed of less than 7 vehicles. 125 mph tests were undertaken between Swindon and Bristol Parkway using HST trailers to prove the braking performance was adequate. As we know Royal Mail controversially decided against the widespread use of rail for mail traffic, and adopted greater use of domestic flights and large road vehicles as the future.

Since that time there has not really been any demand for the 125 mph capability of the locomotives. Some Network Rail routes have imposed blanket restrictions on them because of their effect on the track. However I have definitely been behind one at 110 mph on the ECML on a Mk 4 set even as stated above it took a long time to get there.

 

[squizzler]

These locos seem to have become a bit crude for the modern UK passenger express scene, but maybe they would be more successful overseas. Iran are major users of Alstom Prima diesel, and have taken Pacers off UK hands in the past. Maybe they would have some?

 

[LNW-GW Joint]

These locos seem to have become a bit crude for the modern UK passenger express scene, but maybe they would be more successful overseas. Iran are major users of Alstom Prima diesel, and have taken Pacers off UK hands in the past. Maybe they would have some?

I don't think any other railway has a requirement for 125mph diesel locos.

 

[najaB]

I do believe that if it ever does have to rescue a Mk4 set speed is something it gets to quite slowly and 125mph? forget about it.

I seem to remember that they do around 90mph on Thunderbird duties, maybe 100mph even?

 

[CosherB]

These locos seem to have become a bit crude for the modern UK passenger express scene, but maybe they would be more successful overseas. Iran are major users of Alstom Prima diesel, and have taken Pacers off UK hands in the past. Maybe they would have some?

'Crude'? Are you having a laugh? They maybe less sophisticated than a 68, but crude isn't a term I'd associate with them.

https://www.flickr.com/photos/rpmarks/4925006202/in/photolist-8vcWL3-6NSh7K-f6sz2U-9D5GwT-oJkn8a-orQDGm-pU9ukF-ebDAT9-an5SUk-8ePJwU-pyRLoN-RqC4BK-pS3XX9-8eqGqz-cMxxTf-6eEVkv-aAxENr-dYMJF9-aAAn1E-W6fQmV-aAxCGM-aAwZoZ-D1TZMz-VTV3vM-aAzFLh-aAzDL1-fSWB9u-fSXM6n-aAwWmK-pBPj6G-kv5mBn-paRqqC-pXetzG-69kucR-7L9776-pod62w-SNRsts-8mtPda-8ePJW3-aTHyht-aAzG3j-aAxEmF-fSXkVJ-fSWjKC-fSWzpY-fSXcP5-fSXyhB-fSWvdw-fSYbSv-fSXKzN

Is this crude?

 

[Deepgreen]

'Crude'? Are you having a laugh? They maybe less sophisticated than a 68, but crude isn't a term I'd associate with them.

https://www.flickr.com/photos/rpmarks/4925006202/in/photolist-8vcWL3-6NSh7K-f6sz2U-9D5GwT-oJkn8a-orQDGm-pU9ukF-ebDAT9-an5SUk-8ePJwU-pyRLoN-RqC4BK-pS3XX9-8eqGqz-cMxxTf-6eEVkv-aAxENr-dYMJF9-aAAn1E-W6fQmV-aAxCGM-aAwZoZ-D1TZMz-VTV3vM-aAzFLh-aAzDL1-fSWB9u-fSXM6n-aAwWmK-pBPj6G-kv5mBn-paRqqC-pXetzG-69kucR-7L9776-pod62w-SNRsts-8mtPda-8ePJW3-aTHyht-aAzG3j-aAxEmF-fSXkVJ-fSWjKC-fSWzpY-fSXcP5-fSXyhB-fSWvdw-fSYbSv-fSXKzN

Is this crude?

Well, the take-away carrier bag is! Seriously, though, the 67s are an odd bunch - almost never used for their designed purpose and seemingly struggling to find useful work. Being Bo-Bo and geared for 125mph, they are far from ideal for freight work, but (Chiltern aside) seem to be rarely used for 100mph, let alone 125mph, passenger work. Their all-purpose description when ordered has never really been exploited.

 

[The Planner]

We timed them at 110mph on the rare occasions WSMR diverted via the WCML.

 

[Deepgreen]

Wasn't there something with brakes as well? Full confidence they could do 125mph, not so much confidence they could stop?

I might be wrong, but i'm sure it was mentioned somewhere.

Would this be when running light (when locos are limited to far less than 125mph anyway) as otherwise the hauled stock's brakes are surely the governor of braking performance?

 

[spargazer]

I don't think any other railway has a requirement for 125mph diesel locos.

Pacers at 125mph? now thats an idea to Test out

 

[squizzler]

'Crude'? Are you having a laugh? They maybe less sophisticated than a 68, but crude isn't a term I'd associate with them.

https://www.flickr.com/photos/rpmarks/4925006202/in/photolist-8vcWL3-6NSh7K-f6sz2U-9D5GwT-oJkn8a-orQDGm-pU9ukF-ebDAT9-an5SUk-8ePJwU-pyRLoN-RqC4BK-pS3XX9-8eqGqz-cMxxTf-6eEVkv-aAxENr-dYMJF9-aAAn1E-W6fQmV-aAxCGM-aAwZoZ-D1TZMz-VTV3vM-aAzFLh-aAzDL1-fSWB9u-fSXM6n-aAwWmK-pBPj6G-kv5mBn-paRqqC-pXetzG-69kucR-7L9776-pod62w-SNRsts-8mtPda-8ePJW3-aTHyht-aAzG3j-aAxEmF-fSXkVJ-fSWjKC-fSWzpY-fSXcP5-fSXyhB-fSWvdw-fSYbSv-fSXKzN

Is this crude?

I'd labelled it crude due to its use of a heavy freight derived 2 stroke engine and DC traction motors rather than its interior styling.

 

[Darandio]

Would this be when running light (when locos are limited to far less than 125mph anyway) as otherwise the hauled stock's brakes are surely the governor of braking performance?

Most likely.

It was just that seemed to recall some talk of cast iron brakes? But I can't for the life of me find the thread, nor do I know whether it had anything to do with 125mph running or not!

 

[87015]

We timed them at 110mph on the rare occasions WSMR diverted via the WCML.

And in fairness, they were more than good for it. I've done "fast" via Weedon enough times and they certainly made you think about quarter mile guesstimates on the Mickey mouse loads. No overspeed when DVT leading of course!!

 

[route:oxford]

Most likely.

It was just that seemed to recall some talk of cast iron brakes? But I can't for the life of me find the thread, nor do I know whether it had anything to do with 125mph running or not!

It was for taking the Caledonian Sleeper up to Fort Bill wasn't it?

The 67s were going through a standard set of brakes on each return diagram.

 

[CosherB]

I'd labelled it crude due to its use of a heavy freight derived 2 stroke engine and DC traction motors rather than its interior styling.

Crude as in well proven and generally very reliable?

And what is your definition of a 'heavy freight' power unit? The Cat C175-16 used in the 68 has a multitude of applications, including ships!

 

[squizzler]

Crude as in well proven and generally very reliable?

And what is your definition of a 'heavy freight' power unit? The Cat C175-16 used in the 68 has a multitude of applications, including ships!

Look, I've nothing against the locos disparagingly referred by some as skips! Yes, My opinion is that the GM 2 stroke lump is a physically heavy motor compared to modern "high speed" 4 strokes like the Cat 175, MTU 4000 and Cummins 95 variously found on fast locos in the UK and USA, as it originated from US freight locos. Also crude as in poor emissions.

The DC traction motors are also an outdated technology and contribute to the bogie mass. All said, it was good in its time but the fact, imo, it seems so much closer to late BR loco in technical sophistication than it is to machines like the Class 68, is a credit to how the state-of-the-art has evolved in the meantime!

 

[Mordac]

Most likely.

It was just that seemed to recall some talk of cast iron brakes? But I can't for the life of me find the thread, nor do I know whether it had anything to do with 125mph running or not!

According to the P5 books, 67004/07/09/11 were fitted with cast iron break blocks for working the Fort William sleeper, and were restricted to 80mph as a consequence. Is this what you were thinking of?

 

[Rob F]

Crude as in well proven and generally very reliable?

And what is your definition of a 'heavy freight' power unit? The Cat C175-16 used in the 68 has a multitude of applications, including ships!

I believe even when they were ordered Roger Ford was quite disparaging of the design, with regard to the diesel engine selected and the axle load and questioned how widespread their use would turn out to be.

Rob

 

[SpacePhoenix]

Would the engines used in a 68 have a hope in hell of fitting inside a 67?

 

[Cherry_Picker]

Would this be when running light (when locos are limited to far less than 125mph anyway) as otherwise the hauled stock's brakes are surely the governor of braking performance?

A 67 can do 125mph when running light. It's actually got dispensation in the rule book, however the places where permissible line speed allows for that on the network are few and far between.

 

[Darandio]

According to the P5 books, 67004/07/09/11 were fitted with cast iron break blocks for working the Fort William sleeper, and were restricted to 80mph as a consequence. Is this what you were thinking of?

Must have been, cheers.

 

[CosherB]

Would the engines used in a 68 have a hope in hell of fitting inside a 67?

What do you mean by that? The current engines in the 68s are no longer meet environmental regulations, and we are led to believe that a Tier III version won't fit.

So the obvious answer to your question is no. Unless you want DRS to remove their engines from the 68s and donate them to DBC for ongoing use in their 67s? But I still don't know if they'd fit.

Do you think that DBC will re-engine their 67s, even though they don't have enough work to keep them all occupied at the moment?!

It's Friday after all .....

 

[TimboM]

A 67 can do 125mph when running light. It's actually got dispensation in the rule book, however the places where permissible line speed allows for that on the network are few and far between.

I bet that was/is some experience - doing 125 mph light engine!