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Post by District Dave on Apr 19, 2007 18:42:46 GMT
I thought you'd all like to have a read of this, and I promise I'll try to keep it reasonably non technical! My trainee and I were 'doing' a couple of Wimblewares today, having picked up at Earls Court West we'd been down to Wimbo and back to Edgware Road. On changing ends it was noted that the only lights on in the cars were the emergency lights - so the lights were cut in (though a quick trip and reset was done - but made no difference). A check of the desk showed that the Motor Alternator (MA) lamps were not lit, so this suggested that we'd lost traction current. We were just going to start checking this when the starter cleared - so surely we must have juice. A quick prod of the MA Set button showed that there was current, but the MA's would not 'set' - i.e. keep running when I let my finger off the button! So, we made our way down to Earls Court - having called the Controller from Paddington and asking for the Train Technician - by means of alternately motoring and holding the MA set button in (you can't do both). At Earls Court I tried all three cabs all to no avail. The TT joined us (we've now taken the train out of service) and he too is puzzled (to say the least). So, empty to PG where the TT tries the same as we have done  to achieve the same result. Quick phone call to solidbond to see if he has any bright ideas (which actually only confirmed my thought that the contactors couldn't be latching for some reason). The TT is of the opinion that there is probably a short somewhere which is why the MA's won't set up from any position, so it was empty to Edgware Road for a changeover, again using the 'motor' 'MA set' technique we'd used on the way down, rather than risk running out of batteries! Brightened up a routine day and, of course, good experience for the trainee! |
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Post by Deleted on Apr 19, 2007 19:04:06 GMT
That must have been strange for the sheep cattle passengers customers to experience - I'm surprised that you didn't get a handle down when in transit between stations.
I also didn't know that a train would actually move with the MAs cut out - surely the batteries would be under heavy strain, having to carry the load from 3 motor cars' worth of camshafts and control gear. I wonder if the fitters at Hammersmith will have to replace the batteries when they fix the MAs.
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Post by Deleted on Apr 19, 2007 19:19:00 GMT
Not too familiar with C stock - but do they have a fault isolating switch ? On A stock the MA set wire goes through the fault isolating switch - which in this scenario would allow you - as long as the fault was in the rear unit - to set your leading MA and get you out of the way , so to speak .
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towerman
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Post by towerman on Apr 19, 2007 19:25:05 GMT
Sounds like the latching mechanism on the MA contactor was faulty.In the days before PEA's if the batteries went flat you could put a control key in the rear cab and get a back feed,got me out of the brown stuff once on the Victoria Line.
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Post by Deleted on Apr 19, 2007 19:36:56 GMT
Seems a bit unusual for the latching mechanism to fail in all driving positions though.
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Post by Deleted on Apr 19, 2007 19:59:25 GMT
Interesting scenario there DD...
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Post by District Dave on Apr 19, 2007 20:24:06 GMT
That must have been strange for the sheep cattle passengers customers to experience - I'm surprised that you didn't get a handle down when in transit between stations. Did lots of PA's at stations telling them that the lights would dim down from time to time and that they'd be on the emergency lights only - in my experience if you tell them something will happen they're OK with it. I also didn't know that a train would actually move with the MAs cut out - surely the batteries would be under heavy strain, having to carry the load from 3 motor cars' worth of camshafts and control gear. I wonder if the fitters at Hammersmith will have to replace the batteries when they fix the MAs. Always one thing one has to watch out for is the drain on the batteries, but the trains will move with the MA's out - until the batteries fail! As I'm sure you'd expect there are steps we take to minimise the battery drain - and hence the reason why I wanted to keep the MA's running 'manually' as far as possible! |
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Post by District Dave on Apr 19, 2007 20:25:46 GMT
Seems a bit unusual for the latching mechanism to fail in all driving positions though. Having just spoken to solidbond on the phone, we are now of the opinion that there must've been a 'bastard feed' somewhere on the MA trip circuit. I hope to find out what the cause was eventually, and I'll try to elaborate on this thread when I do. |
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Oracle
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Post by Oracle on Apr 19, 2007 20:37:46 GMT
I am very impressed at the efforts taken and your trainee clearly had a very educational trip [quasi-pun unintentional].  Also I loved the "Phone a friend"! Presumably after using up the other lifelines: a) ask the punters on the train for their opinion, and b) pulling half the equipment out leaving only half remaining.  |
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Post by Deleted on Apr 19, 2007 20:45:30 GMT
I think DD took the option of Third Sam in the classic British Transport Films short video... Took a metaphorical approach!
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Post by Chris M on Apr 19, 2007 21:20:25 GMT
Also I loved the "Phone a friend"! Presumably after using up the other lifelines: a) ask the punters on the train for their opinion, and b) pulling half the equipment out leaving only half remaining. I wonder how long it will be before someone posts a question on this forum about a current fault  I'm sure there are plenty of us who would not hesitate to comment! |
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Post by Deleted on Apr 19, 2007 21:23:35 GMT
Off LU, but recently a train had a broken window wiper and the driver had to ask the passengers for some string or tie or summat! Mildly amusing to read that in the railway press!
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Post by Deleted on Apr 19, 2007 21:35:14 GMT
On a VT at Rugby, probably.
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Post by Deleted on Apr 19, 2007 21:37:43 GMT
I think it was indeed on a VT service...
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Oracle
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Post by Oracle on Apr 19, 2007 21:58:09 GMT
On a 444 that I was on a side window was smashed by a rock thrown up by the train near Basingstoke. On arrival at Winchester the female Guard promptly produced from somewhere clear plastic film and gaffer tape to stuck over the hole etc. very effectively. No train cancelled, punters delivered home and the Guard was nonplusssed ... all in a day's work!
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Post by chrish on Apr 20, 2007 15:06:17 GMT
Seems a bit unusual for the latching mechanism to fail in all driving positions though. Having just spoken to solidbond on the phone, we are now of the opinion that there must've been a 'bastard feed' somewhere on the MA trip circuit. I hope to find out what the cause was eventually, and I'll try to elaborate on this thread when I do. I realise this is only agreeing with what you have written, but I mentioned this to my stock trainer at Hammersmith today, and he said he had had a very similar defect which turned out to be the MA trip button was just stuck in, hence why the circuit tripped as soon as you let go of the MA set button. So, I'd agree with the experts on this (not that I'd dare disagree!) |
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Post by Deleted on Apr 20, 2007 16:23:41 GMT
Do the trip/set pushbutton switches appear visibly depressed? I would imagine there would be red faces all around when the head fitter at Hammersmith walks up to DD and solidbond and shows them a broken button ;D ;D ;D
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Post by chrish on Apr 20, 2007 16:46:17 GMT
Do the trip/set pushbutton switches appear visibly depressed? I would imagine there would be red faces all around when the head fitter at Hammersmith walks up to DD and solidbond and shows them a broken button ;D ;D ;D No, just a normal push button. Just depresses and pops back out when released! I would have thought you'd have more confidence in our esteemed leader!  ;D |
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solidbond
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Post by solidbond on Apr 20, 2007 17:17:14 GMT
Ahh - but since the MA trip circuit goes through the control key, once the key was removed, that particular button would not work anyway. Thus, the fact that the MA's were tripping out from ALL cabs means that it couldn't be a button stuck in - unless they ALL were ;D ;D |
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Post by Deleted on Apr 20, 2007 18:00:22 GMT
Ahh - but since the MA trip circuit goes through the control key, once the key was removed, that particular button would not work anyway. Thus, the fact that the MA's were tripping out from ALL cabs means that it couldn't be a button stuck in - unless they ALL were ;D ;D Touche'! Have you found out what the defect is yet? |
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Post by Deleted on Apr 20, 2007 18:15:05 GMT
If it is a 'bastard feed' on the MA trip wire - which sounds like the most probable cause - then that is going to be a nightmare to locate and rectify , i would have thought.
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Post by chrish on Apr 20, 2007 19:03:25 GMT
Ahh - but since the MA trip circuit goes through the control key, once the key was removed, that particular button would not work anyway. Thus, the fact that the MA's were tripping out from ALL cabs means that it couldn't be a button stuck in - unless they ALL were ;D ;D Good point... and well made!  Oh well, at least I can claim I'm not qualified as yet! **Blames Ignorance** ;D |
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to achieve the same result.
I'm sure there are plenty of us who would not hesitate to comment!
;D
