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Post by Chris W on Dec 14, 2006 1:17:05 GMT
On my desktop I have an image of a 6-car unrefurbed D stock train at Earls Court taken at the inaugural DD forum meet back in August 2005. At the head of the train heading eastbound to Upminster is car 7075 - what struck me was the need for a coupler on the 70** & 71** DM cars given that they only ever face the front or back of 6-car trains (the cab end is destined never be attached to another car in service). Whilst I can therefore see the logic behind couplers on the 75** series of 3 car units (they at some point would face inwards as part of a 6-car train), why were couplers added to the front of the 70** & 71** DM fleet? I appreciate depot shunting might answer part of the question as well as uniformity of the DM stock if cars needed to be swapped between units  - I was just wondering, thats all  |
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Colin
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Post by Colin on Dec 14, 2006 2:03:29 GMT
How about a broken train? There are one or two defects that require a 'push out' as a solution. A 'push out' can be a defective train driven from the rear (by a second person) or use of another train attached to the rear. On single ended units (70xx & 71xx), the coupler is mechanical only - ie, no air or electrical connections *. Double ended units (75xx) have full couplers - ie, air and electrical connections present. A, C & D stocks can all couple to each other - but 'pressphans' must be used to prevent eratic electrical problems. * = limited electrical connections are present to enable things like cab-cab communication, though we generally always use 'pressphans' now which ensures no electrical problems. |
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Post by tubeprune on Dec 14, 2006 8:49:24 GMT
* ....though we generally always use 'pressphans' now which ensures no electrical problems. So what is the procedure for communication between the T/O at the front of a defective train being pushed and the T/O of the pusher? Do you need someone in the back cab of the defective train to shout messages across the coupler? |
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Deleted
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Post by Deleted on Dec 14, 2006 10:43:28 GMT
You use the connect portable radio handet on a direct call to the other operators connect portable radio handset. (or even direct call from train cab to train cab using onboard connect)
In the event of their failure to function "back to back" radio's must be used.
Previously the electrical connections (when presphan shields not used) allowed cab to cab communications using the cab to cab pa system.
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Deleted
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Post by Deleted on Dec 14, 2006 11:51:56 GMT
I thought presspahns were used only when C and D (or A and D) stock were participating in a pushout, due to the modified electrical stud pattern on the D stock Wedgelocks due to the refurbishment.
Why use them when D stocks are pushing D stocks?
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Colin
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Post by Colin on Dec 14, 2006 13:43:27 GMT
Refurbished D stocks are not compatible with un-refurbished D stocks (*I THINK* ;D) - we now have a generic instruction to use the presspahns at all times as it prevents a forgetful driver from failing to use them with certain combinations of stock.
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solidbond
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Post by solidbond on Dec 14, 2006 17:53:16 GMT
Refurbished D stocks are not compatible with un-refurbished D stocks (*I THINK* ;D) - we now have a generic instruction to use the presspahns at all times as it prevents a forgetful driver from failing to use them with certain combinations of stock. We do? The first I've heard of it  I tell trainees, if it is a refurb D to a refurb D, or a non-refurb to a non-refurb, then presspahns are not needed. In all other cases they must be used. Prior to the introduction of Connect, hand-held radios with back-to-back facility, would need to be provided. |
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Deleted
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Post by Deleted on Dec 14, 2006 23:44:03 GMT
The only time I've ever been involved in a push-out, we decided to use the presspahns just in case, since there seemed to be no advantage in NOT using them!
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Colin
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Post by Colin on Dec 15, 2006 3:42:17 GMT
Indeed. If I wasn't told that directly during stock refresher training, well............I've certainly been under that impression for a while now  ;D ;D ;D |
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TMBA
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Post by TMBA on Dec 15, 2006 16:15:24 GMT
They also split the units every now and then in the depot and couple them up to different units. Ive had occasion that a middle cab has been used at the front of a unit.
What ever happened to that double ended double unit refurb? is it still around or is that now just a single?
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Deleted
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Post by Deleted on Dec 16, 2006 0:58:57 GMT
Indeed. If I wasn't told that directly during stock refresher training, well............I've certainly been under that impression for a while now ;D ;D ;D I WAS certainly told it during a stock refresher. But I also accept solidbonds notation that it's not actually necessary with cetain D to D couplings. |
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Deleted
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Post by Deleted on Dec 16, 2006 1:05:33 GMT
They also split the units every now and then in the depot and couple them up to different units. Ive had occasion that a middle cab has been used at the front of a unit. What ever happened to that double ended double unit refurb? is it still around or is that now just a single? I'm pretty certain there are no double to double couplings at the moment ...but no doubt that may change as trains return from or prepare to depart for Refurb. There is no such thing as a middle cab on a D stock, in the sence that any double ended unit can be used at either end of a 6 car District line train and what may be a middle cab when working at the east end will be a front cab when working at the west end of a train. That said a small number of cabs seem to have pretty permenant homes in the middle, such cabs tend to be notably grotty if they should escape to an outer end !! |
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Colin
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Post by Colin on Dec 16, 2006 1:42:48 GMT
I walked through a train the other day, with a double ender at one end - and it was quite obvious why the west end cab was in the middle......no drivers seat, whole PA panel missing, cabinet door missing on offside and the offside windscreen wiper motor cover was missing!
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- I was just wondering, thats all 
I tell trainees, if it is a refurb D to a refurb D, or a non-refurb to a non-refurb, then presspahns are not needed. In all other cases they must be used.
