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Also note that 43014 (and 43123) had ETH cable boxes both ends and through wiring (the jumper socket is clearly visible on that shot on bottom right hand corner) which would have allowed the Class 91 to go on front of the power car and still send ETH down to the train if so desired- they gained this for the WCML DVT trials.

 

 

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4 hours ago, GordonC said:

 

Is that Leeds?

 

Yes, the old platform 6.  The tests used the sleepers as there were insufficient spare hst sets. Also they had not converted all the TGS. During the tests the HST was idle all the time as it only covered the PCs own auxiliaries. This was not ideal; from a discussion with another student who had a summer placement as a travelling hst fitter, once they connected the DVT to a full hst set it was doing a constant 900rpm for the ETH which was even worse. At some point they connected the traction system to the TDM and got the best part of 9000HP:D

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22 minutes ago, Bomag said:

Yes, the old platform 6.  The tests used the sleepers as there were insufficient spare hst sets. Also they had not converted all the TGS. During the tests the HST was idle all the time as it only covered the PCs own auxiliaries. This was not ideal; from a discussion with another student who had a summer placement as a travelling hst fitter, once they connected the DVT to a full hst set it was doing a constant 900rpm for the ETH which was even worse. At some point they connected the traction system to the TDM and got the best part of 9000HP:D

8,730HP was the quoted figure. Also don't forget, they couldn't release Mk3 rakes for test trains as they were pretty much fully deployed on passenger service, so the surplus/spare sleepers did what they wanted them to do in that they provided a load for the Class 91 to play with and through wiring for the TDM control.

HST power car on fast idle is 1000rpm but it doesn't provide ETH to the train, can only send 415v three phase down HST trailers. Having the ETS running in that formation is still essential to keeps the power cars own batteries and auxiliaries alive- and ETS also powered the headlights in that era.

Edited by fiftyfour fiftyfour

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8 hours ago, fiftyfour fiftyfour said:

8,730HP was the quoted figure. Also don't forget, they couldn't release Mk3 rakes for test trains as they were pretty much fully deployed on passenger service, so the surplus/spare sleepers did what they wanted them to do in that they provided a load for the Class 91 to play with and through wiring for the TDM control.

HST power car on fast idle is 1000rpm but it doesn't provide ETH to the train, can only send 415v three phase down HST trailers. Having the ETS running in that formation is still essential to keeps the power cars own batteries and auxiliaries alive- and ETS also powered the headlights in that era.

 

A bit of invisible writing there, I didn't forget that they were short of HST sets as I clearly mentioned it. Also, as mentioned they were still converting the 8 TGS with buffers and drophead buckeye, the NL spare TGS 44100 was regularly seen deputising in sets while they were modified (44100 was still in B/G while the rest of the sets were in ICE or ICS). HSTs DVT did indeed need the engine running to power the TDM system. The information I was given was that if the power car was not supplying the 3 phase ETH to a set it would run at whatever the minimum fuel flow was set to (whether this was to both banks on the Valenta I am not certain). Once they subbed the sleepers with the HST coaches the DVTs never ran below the rpm needed to power the 3 phase ETH. Unlike where there was two PC and they would tend to switch which one was providing the ETH, never going to full idle was not conducive to various bits (explained to me as something related to the exhaust system and confirmed in the link) and going to the full 1500rpm cleaned the system out.

 

One thing which is not clear is what was the speed they tested using the MK 3 sleepers, from the link it is implied they ran at 125mph. In which case it may have been a bit lively! It was bad enough in the TGS southbound when in service.

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All sorts of problems with leaving a HST power car on idle for long periods, especially so whilst dragging it around. Commutator glazing on the traction motors caused some failures when power was later applied was the initial "find" and then oil being carried over into the exhaust system resulted in a couple of fires was the final straw that resulted in the power cars powering in the Class 91/HST combo. The latter worked quite well as the power car was doing more than its fair share upon restarting the train whilst the Class 91 sat there and pondered the meaning of life for a while before putting down power, then when the Class 91 woke up it would accelerate the train up to full speed far quicker than any HST ever could have done!

 

I hadn't realised the ETS needed to be on to run the TDM system but I guess it must get its power from somewhere (so from that I'd assume a Mk3 DVT dies quickly if starved of ETH?) and running up the ETS would have been the only option even if trailing and the headlights were not required.

 

You'd like to think they stuck to 110mph with a SLE/SLEP in consist but you never know...!!

 

 

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I thought the LH mk3s were 125mph max anyway, it's just that in normal running on the WCML they were restricted to 110mph (due to the locos used?)

Test trains are a slightly different matter as they are often authorised to run at speeds in excess of normal limits (for the track or stock).

One of the other factors involved with HSTs and DVTs is that the air brake is propogated from both ends at the same time - if there's a problem with this then the top speed is limited to 110 (I think)

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28 minutes ago, keefer said:

I thought the LH mk3s were 125mph max anyway, it's just that in normal running on the WCML they were restricted to 110mph (due to the locos used?)

Test trains are a slightly different matter as they are often authorised to run at speeds in excess of normal limits (for the track or stock).

One of the other factors involved with HSTs and DVTs is that the air brake is propogated from both ends at the same time - if there's a problem with this then the top speed is limited to 110 (I think)

 

There are two types of BT10, one rated to 125 mph and one to 110 mph. As explained to me this was identified as suspension settings etc, but in a previous post somebody mentioned that the frames are different. It is not clear if it is unsafe to run a 110 mph rated BT10 at 125 mph or just that the ride would not be acceptable for a passenger service. 

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And according to some Intercity (LMR) paperwork I got back in the 90s, that sleeper trains were not to be run above 80mph without authorisation. I can't find the paperwork in question but the implication was that this was for the comfort of sleeping car passengers. I wonder how late they had to be to get the authorisation.

 

Not really relevant to the test train being discussed, but interesting to know.

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It was the same even with the mk 1 sleepers, they were fitted with CW/B5 bogies (100mph) but services were probably only timed for about 80mph max

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AFAIK sleeper trains were (and still are) timed to run at 80mph but authorised for 100mph if late; Not sure if any message (from Control) was required or if it was just left up to the Driver.

 

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