NXEA temporary loco hauled service

[Re6/6]

I saw in this week's 'Rail' magazine that NXEA are running some loco hauled replacement services for shortage of DMUs in the Yarmouth area. The pictures show a 47/8 and a 20 top'n'tailing a three coach train including a DVT. Why the need for the 20, when a DVT is in the consist?

[Glorious NSE]

DVT is not push-pull compatible with either of the loco's, but is still required in the rake as the brake vehicle.

[Re6/6]

Thank you Martyn. There had to be a logical answer!

[Rhydgaled]

DVT is not push-pull compatible with either of the loco's, but is still required in the rake as the brake vehicle.

Couldn't a 47/7 have been used instead? As 47/7s have TDM wouldn't that mean it could work push-pull with the DVT?

[Bomag]

Couldn't a 47/7 have been used instead? As 47/7s have TDM wouldn't that mean it could work push-pull with the DVT?

 

The TDM in the 47/7 (and 67) is incompatible with the system in Cl86/87/89/90/91, DVT and rebuilt DBSO. When I was in the PW design section Norwich in 1990 one of the technology bods mentioned that the electric version used a different distribution curve for power/acceleration characteristic and if you plugged a 47/7 into a rebuilt DBSO and put it on max power it would melt the TDM control system on the 47 (or something like it).

 

The DVTs on the Wrexham and Shropshire trains had to be modified to work in push pull mode with the 67s

[hairyhandedfool]

The 47/7s and 67s are RCH fitted, not TDM, although exactly what the difference is I can't say. The only diesel locos I know of that had TDM were the buffer fitted HST power cars, but they no longer carry the equipment.

 

 

[sooty]

The 47/7s and 67s are RCH fitted, not TDM, although exactly what the difference is I can't say. The only diesel locos I know of that had TDM were the buffer fitted HST power cars, but they no longer carry the equipment.

 

RCH stands for Railway Clearing House. A Railway Clearing House was where equipment was tested & passed for use on the railway & these cables have been know as RCH cables since they're introduction originally to control train lighting.

The RCH cables on RES 47/7's & Skips were for working with PCV's (Propelling Control Vehicle) when propelling stock in or out of mail terminals. The 47/7's or Skips & PCV's really didn't have multiple working as such. The RCH cables were used for cab to cab comunication system so that the driver in the PCV could comunicate with the driver in the loco when propelling.

 

TDM stands for Time Division Multiplex system. Where by electronic signals are sent in the form of electronic pulses between 2 loco's or loco & DVT.

 

The TDM fitted to the buffer fitted HST's power cars when they were acting as surrogate DVT's with the 91's was type for electric loco's unlike that fitted to the first 17 47/7 for the GLQ to EDB push pulls.

[davep101]

as seen in many mags, the chopper only actually worked one day, its normally from the anglia based drs thunderbird stable, 47712/832, due to a prob with 832 the chopper was turned out..it maybe worked two days cant quite remeber now, i got the gen the other day 37194 nearly got used but then instead they put a 57 out on it, again i believ because 832 had burst, whod have thought in 2010 all this random traction out and about!!! dave

[Rhydgaled]

So TDM on 47/7s only works with non-rebuilt Mrk2f DBSOs, correct? Were all the Mrk2f DBSOs rebuilt?

Now, Intercity 125s do not have TDM and I think they normally run with both class 43 locos providing power with nobody in the rear cab. So are there any other desiel locomotives that can do this without needing a driver in both locos? (One class that I expect is able to do this is the special Nightstar 37s (37/6?).) I know several classes have multiple working systems, but do these work with a rake of coaches in between?.

 

Also, can the TDM (or another system) fitted on the 91s, 90s, 89 "Avocet", 87s and 86s be used to control a second loco on the other end (ie. an Intercity 225 with the DVT swapped for a 2nd 91 with both 91s providing power)? Talking of 225s with 91s at both ends, didn't this happen once on a test of ECML catenary? if so, are there any pics or videos of it anywhere?

 

 

[Chris.D]

The HST Mk3's have wiring installed in them to allow the commands to pass through to the rear power, like the RCH on the loco hauled MK3's.

 

Yes, the T.D.M can control another loco/s (I can't remember the maximum number) as long as the connecting cables are the same, i.e. they both have RCH fitted. The 'Two Pan Testing' did happen with two Cl.91 powering back in summer time of 2009, but pictures and videos of it are scarce as it was done during the night. However, I have seen one picture of it in Rail Express.

 

Cheers

 

Chris

[Rhydgaled]

Yes, the T.D.M can control another loco/s (I can't remember the maximum number) as long as the connecting cables are the same, i.e. they both have RCH fitted. The 'Two Pan Testing' did happen with two Cl.91 powering back in summer time of 2009, but pictures and videos of it are scarce as it was done during the night. However, I have seen one picture of it in Rail Express.

Thanks for confirming that. I've heard the acceleration of the class 91 hauled trains with the buffer-fitted Class 43s acting as DVT and providing power was quite impressive, with two 91s the acceleration must be mindblowing. I'd like to know the power to weight ratios of that compared to some of today's multipule units.

 

The HST Mk3's have wiring installed in them to allow the commands to pass through to the rear power, like the RCH on the loco hauled MK3's.

Do mrk2f coaches have through wiring? since as far as I know they are the newest stock currentlly off-lease in large qunatities.

[Bomag]

Thanks for confirming that. I've heard the acceleration of the class 91 hauled trains with the buffer-fitted Class 43s acting as DVT and providing power was quite impressive, with two 91s the acceleration must be mindblowing. I'd like to know the power to weight ratios of that compared to some of today's multipule units.

 

Do mrk2f coaches have through wiring? since as far as I know they are the newest stock currentlly off-lease in large qunatities.

 

I think 2 CL91 may have the same limitation as the Eurostars on the ECML i.e you will draw to much power (current?) and trip it out - 12600hp vs 16000hp. The Cl91+DVT was rather nippy when both were in use, without the limitations of TPWS KX to Peterborough was regularly sub 42 minutes and KX to Doncaster was 85 mins. Also the speed down Stoke Bank was regularly 128-130mph as, I was told by a travelling engineer (much needed at the time), some of the HST over speed detectors had to be desensitised. The only downside was that the ride in the TGS was terrible Southbound.

 

Any BR Standard RCH fitted stock should work in push pull but is likely to be unreliable. I read that the Scotrail Mk3s had to have the wires shielded to cut out interference. I think this does not apply as much to the electric loco version which AFAIK had the ability to compensate.

[Rhydgaled]

I think 2 CL91 may have the same limitation as the Eurostars on the ECML i.e you will draw to much power (current?) and trip it out - 12600hp vs 16000hp. The Cl91+DVT was rather nippy when both were in use, without the limitations of TPWS KX to Peterborough was regularly sub 42 minutes and KX to Doncaster was 85 mins. Also the speed down Stoke Bank was regularly 128-130mph as, I was told by a travelling engineer (much needed at the time), some of the HST over speed detectors had to be desensitised. The only downside was that the ride in the TGS was terrible Southbound.

When the switch was made to Mrk4s and DVTs were they still used in normal service at over 125mph? I assume the ride was better with Mrk4s at such speeds, due to them actually being designed for it while the Mrk3s were designed for 125mph.

 

Any BR Standard RCH fitted stock should work in push pull but is likely to be unreliable. I read that the Scotrail Mk3s had to have the wires shielded to cut out interference. I think this does not apply as much to the electric loco version which AFAIK had the ability to compensate.

Ok, what about top and tailing deisels with both providing power? and are any Mrk2f DBSOs still compatible with 47/7s?

[Bomag]

When the switch was made to Mrk4s and DVTs were they still used in normal service at over 125mph? I assume the ride was better with Mrk4s at such speeds, due to them actually being designed for it while the Mrk3s were designed for 125mph.

 

Ok, what about top and tailing deisels with both providing power? and are any Mrk2f DBSOs still compatible with 47/7s?

 

 

The origonal ride of the Mk4s was teribble at 125mph, much worse that Mk3s. I have no idea how they found this out but they rotated the bogies by 180 degrees which gave a significant imprivement in ride. It took a bit longer to sort out the explosive backfeeding of the toilets when the went through tunnels!

 

 

AFAIK you can top and tail two 67s using the RCH cables - the DBSOs are not now compatible with 47/7 but seem to be in use with Network Rail's yellow peril Cl31s

[Steadfast]

The Network Rail DBSOs and test trains are through wired with blue star to allow compatiblity with class 31s.

There are also a couple of sets of through wire passenger mk2s, the Wessex sets top n tailed with 31s utilised these

HTH

cheers

 

jo