I thought the DVT's applied the brakes directly, but sent the throttle signals to the Class 91 via TDM.
What do the brake control unit's do exactly?
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Slightly off topic, but this photo illustrates it well, so i'll ask here as it has been puzzling me for a while.
What has caused that diagonal dark line near the pantograph on the Class 91? I'm guessing it's just muck from the pantograph. I ask because I have noticed that it is on most Class 91's, but I haven't noticed it until recently.
Wouldn't it have been sensible to have found out about how the brakes on a Mk IV Set, or a 125 work, before you start attempting to demonstrate your vast traction knowledge?
Its probably the drain hole for the pan well and the rain water is picking up all the dirt before draining out which is staining the sides.
I thought it was something to do with dirt. I didn't know about the drain holes though. Presumably the new silver livery makes it more visible than the previous dark blue livery.
Seems like it, silver does not seem to weather well...
Didn't someone find that out before, when they painted ECML High Speed Traction silver grey ..... back in the 1930s.....![]()
There is no reason in theory why this formation couldn't do 125 mph as both the leading and trailing parts have E10 (or equivalent) brake valves linked by TDM.
What is stopping it going faster than 110 mph is the screw link coupling between the DVT and 91. Had the DVT's been fitted with Buckeyes at their nose end then 125 wouldn't be a problem.
If the 91 is on the head end of a DVT or the train is in reverse formation, the most likely cause is indeed the TDM equipment. That being the case the rear 91 would be uncontrollable and therefore dead in transit.
1. The rear 91 is towed dead. How can the TDM be operational?
2. What must be done to the brake control unit (it's generiacally called an E70 BTW), in such a situation, on any loco so fitted?
3. If you can point me in the direction of any official railway document, stipulating a reduced speed when using an emergency screw link coupling in in this situation, I would very much like to see it.
If the 91 is on the head end of a DVT or the train is in reverse formation, the most likely cause is indeed the TDM equipment. That being the case the rear 91 would be uncontrollable and therefore dead in transit.
Wether there is a TDM connection at the head end of the DVT or not I cannot say. Would be interested to know If driver guard communication would still be operative under this form of working of if they would resort to green flag/RA despatch
I remember Lawrence hill. Mess room banter at the time suggested the driver could have cleared a couple more hoppers and the bridge had he opened up instead of hitting the brakes!
http://www.flickr.com/photos/bonedome/6821602701/
All class 90,91 Mk4's and Mk 3 DVT's (at the gangway end only) have a UIC data cable.. Its on a 90 here in the pic between the air pipes on the left side of the buffer beam.. That is how the TDM signals are sent.
That would be one youtube video!! Can just hear the "bedoing" of the springs and the 67 hopping over the bridge!
So nothing at the pointy end of the 91 or DVT then?
Bedoing! LMFAO picturing it![]()
1. TDM would work off the batteries of the loco (and in the formation being discussed on this thread,the ETS.....)
2. You are getting mixed up.. the E70 (and wrong use of such) landed a 67 on top of a HAA at Lawrance Hill in Bristol.... TDM is different! we are not talking top and tail here!
3. I could list every referance to the subject of couplers.. Do you want me to list them? I am more than willing to trawl through every document, scan them and post them..
It is a rule (since 1951!!) that all high speed trains need a form of automatic coupler.. If they derail etc a buckeye is a minimum standard.. Keeps the coaches upright and in line..
Just because you are unaware of the rules does not mean they do not exist!!
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I can list date and trains when this happened..
Going to post a ton of stuff up.. Regards TDM and AC multiple working!