Hi informed today that the D78 RAT Train this morning in Northfields depot sorry no photo i`am on sick leave. FISH7373 81C NFP
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Last Edit: Oct 12, 2017 16:36:06 GMT by Dstock7080: thread title adjusted
Biography N/A Location london Interests railways Occupation tube lines Northfields railway depot Piccadilly line trains project engineer Local Railway southall railway depot 81c fitter Full Name kevin william fisher www.flickr.com/photos/fish7373/
Post by whistlekiller2000 on Nov 1, 2016 16:20:37 GMT
It reads (in the article mentioned above) that the reason for replacing the A Stock RAT with a D Stock unit is that the A Stock isn't capable of being adapted to the new 750v current being rolled out on the SSL whereas the D Stock is. I assume this means there'll be no more A Stock heritage runs as a result. Would this also have an impact on Sarah Siddons and other heritage stock?
"Clever monkeys with technology Barely out of the caves and the trees......"
The A stock has actually had mods for compatibility with 750V supply, so the article mentioned is a bit out on that detail. Interesting that the D78 RAT has some motoring troubles. Direction wires, I wonder? The first ever 6 car test over 36 years ago had one of the cars trying to go the other way I recall...
Sarah worked for a time on the Southern Region 3rd rail network I believe, so 750V should not be an issue.
That's true for the general supply voltage, but it is the 890V regenerative braking voltage that requires mitigation, something that would not have existed when Sarah Siddons worked railtours on the Southern Region.
Directional control wasn't the issue, it was more general problems with obtaining traction and going into parallel. No doubt the team at Acton will sort it out. Given the significant reconfiguration there is only so much that slow speed moves around the yard can tell you.
The equipment may be rated for higher voltages, but particular items like the MA have their output controlled by a MAR set at a fixed value. Part of the mitigation works involves changing out the MAR for an 'electronic MAR' that senses the traction voltage and changes the output to prevent over-voltage of the auxiliaries e.g. gassing the batteries.