Stupid idea- putting a pantograph on HSTs

[Darandio]

It only worked with the HST remote controlling the 91 as a push-pull, it could never provide diesel traction power, nor be controlled from the 91's cab.

This suggests different......

http://www.traintesting.com/ic225_2.htm

Initially the DVT's power unit was only used to supply ETS for the Mk3 coaches, as they differed from the Mk4's, and hence the engines were only running at approx 1000 rpm, just above idling. However, prolonged use of the power cars in this way lead to an excessive build up of un-burnt fuel in the silencers and this eventually lead to fires. One occurred at Hornsey, just outside Ferme Park, and this brought the OHLE down too. After a repeat performance it was decided that the PC engines should be powered up as normal and this then meant that the test trains had a combined available power of over 7000 HP. A modification to the TDM control arrangements allowed the engine to be controlled from the class 91 and an increase in speed up to the maximum of 125 mile/h was accomplished with ease!

 

[najaB]

This suggests different......

I think that rebmcr meant that the power car was never used provide traction power when off the wires, so it wasn't a bi-mode.

 

[Darandio]

I think that rebmcr meant that the power car was never used provide traction power when off the wires, so it wasn't a bi-mode.

Ahh okay, misunderstanding then.

 

[Jack Hay]

It only worked with the HST remote controlling the 91 as a push-pull, it could never provide diesel traction power, nor be controlled from the 91's cab.

So not no bi-mode then. I misremembered that. But still the simplest way to make an electric HST !

 

[najaB]

So not no bi-mode then. I misremembered that. But still the simplest way to make an electric HST !

It wouldn't work. The performance when off the wires would be worse than a HST with one dead power car (a Class 91 weighs 81 tonnes, as compared to 70 tonnes for a HST power car).

 

[dubscottie]

I think that rebmcr meant that the power car was never used provide traction power when off the wires, so it wasn't a bi-mode.

It was though. There is a YouTube video of the power car propelling the 91 with its panto down.

It was when some storm brought down the wires around Sandy IIRC. I am almost sure the power car was used on the Leeds-Bradford section being controlled from the 91 in one direction.

 

[Bald Rick]

It wouldn't work. The performance when off the wires would be worse than a HST with one dead power car (a Class 91 weighs 81 tonnes, as compared to 70 tonnes for a HST power car).

An extra 10 tonnes on a train weighing the best part of 400 is not going to make much of a difference. Besides, less powerful locos regularly hauled much heavier passenger trains.

 

[najaB]

It was though. There is a YouTube video of the power car propelling the 91 with its panto down.

I doubt that was a regular occurrence though. Mk 4s weigh more than Mk3s and the Class 91 weighs more than a Class 43 - performance on one powercar would be pretty poor.

 

[najaB]

An extra 10 tonnes on a train weighing the best part of 400 is not going to make much of a difference. Besides, less powerful locos regularly hauled much heavier passenger trains.

A HST with a single power car already struggles to keep time - it can do it, but it's not easy. It would be even less so with an extra ten tons added.

 

[Bald Rick]

A HST with a single power car already struggles to keep time - it can do it, but it's not easy. It would be even less so with an extra ten tons added.

Agreed a single power car struggles to keep time, and it's not desirable. But an extra 10 tonnes - 2% of weight is negligible. Gross train weight can vary by up to 30% simply by passenger load.

 

[43096]

It was though. There is a YouTube video of the power car propelling the 91 with its panto down.



It was when some storm brought down the wires around Sandy IIRC. I am almost sure the power car was used on the Leeds-Bradford section being controlled from the 91 in one direction.

Do please explain how that would work. How does the 91 control anything with its pan down, given that it needs power for things like the TDM system.

 

[dubscottie]

Do please explain how that would work. How does the 91 control anything with its pan down, given that it needs power for things like the TDM system.

You would need to ask someone that was involved with them in 1989/90.

There are pics in mags from the time and a video that I am trying to find (99% it is on Avocet1989's YouTube channel) so it DID happen.

I am more than happy to scan the articles and post them if you don't believe me.

 

[xotGD]

So we put 91s at one end of each HST set and 90s on the Mark 4 sets, and VTEC can run a full electric service under the wires.

 

[najaB]

So we put 91s at one end of each HST set and 90s on the Mark 4 sets, and VTEC can run a full electric service under the wires.

Or, alternatively, let them use the Class 800s that are already being built for them.

 

[GusB]

So we put 91s at one end of each HST set and 90s on the Mark 4 sets, and VTEC can run a full electric service under the wires.

Er... what happens when the wires stop? The Chieftain isn't going to do well with one power car and a 91 on the other end!

 

[gimmea50anyday]

The 91 with surrogate HST DVT used mk3's. As HST used a 3 phase 415v ac ETH whereas LHCS uses 1000v DC ETH thats why the PC constantly ran at idle. Not only did this cause exhaust fires but also glazing of the traction motors. Reactivating the HST DVT traction capabilities really did supercharge the trains, they shifted like stink on a stick! XD

Im guessing the 91 was DIT on the rear, but if it was on the front it must have run on batteries as the ETH systems werent compatible as mentioned above. Obviously there would be no traction but the cab can still power up and otherwise operate for a limited period of time

Back then a HST typical formation was 8+2. The EC HST only became 9+2 in GNER days, so although weight would still be an issue, it is suprising how much a difference in performance that extra coach makes. 9+2 HSTs struggle with one PC down.

 

[GrimShady]

I read somewhere that both 91 & 43 were controllable from both ends.

 

[mark-h]

With hindsight it would have been better to make some (bi-mode) electric HSTs for the ECML and not tried to electrify the line up to Scotland on the cheap.

The ECML overhead wiring is still causing problems to this day due to its use of headspans.

 

[AndrewE]

I remember seeing a Special Notice for a test run when the APT was under development...

HST power car (under power) on the front out of one of the northbound Crewe bay platforms
2 APT power cars
something else in the way of a test car or two and
some kind of back cab for setting back to repeat the test.

Apparently it went like a rocket, over 100 mph well before it was out of Crewe town I was told!

A

 

[gimmea50anyday]

I read somewhere that both 91 & 43 were controllable from both ends.

Under the wires yes, once they figured out they were killing the engines by idling them but there were instances where the 91 was pan down for whatever reason leaving the 43 to provide sole traction power