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Post by Deleted on Sept 28, 2016 15:21:19 GMT
Greetings from Mansfield, Massachusetts, USA. I have only visited London twice, and both occasions were in the 1980s.
Earlier this week I watched a cab view Youtube video of Piccadilly line stock driven from High Street Kensington to Northfields, then into Northfields Depot. I am aware of the distinction between subsurface and tube infrastructure and stock, also that District and Piccadilly lines have jointly operated trackage where both kinds of stock are seen. However, the map does not show Piccadilly service to High Street Kensington which I understand to be subsurface territory. I suppose this must have been some special non-revenue circumstance.
Here is my more interesting question. The last three minutes show the train entering a modern shed at Northfields Depot. There is an inspection pit below the running rails. I do not think I see a third rail while the train is over the inspection pit, although perhaps there is one not evident to my view. But there is certainly no fourth rail (because, like, there is a pit instead). So how is the train getting power to traverse over the inspection pit?
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Post by Deleted on Sept 28, 2016 15:34:19 GMT
welcome to the forum, from my knowledge while in the depot the rear of the train on the 4th rail would power the set into the depot while in the sheds. inside the depot set will use a 'socket' on the sides to connect to the overhead wires in place in the sheds. this link will help with more details www.districtdave.co.uk/html/current_supply.html |
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Post by domh245 on Sept 28, 2016 15:36:21 GMT
Hi, welcome to the forum! I suspect that in the video you describe, the train is simply coasting (or as suggested above, powered from the rear) as it traverses the inspection pit. Once stopped, the depot staff can then attach a power supply to the train which it can then get power from to let it draw forward onto a power rail.
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Post by Deleted on Sept 28, 2016 15:42:00 GMT
As it drives into the shed and over the pit, it's drawing its power from the rails outside the shed. As in, it will take the length of the train before the entire thing is off juice. All the while it's travelling into the shed, some of the train's shoes are still in contact with the conductor rails outside the shed, providing progressively less power as more and more shoes go off juice. The train will either stop with at least the rear car still on juice, or it will draw all the way in. Obviously it'll have to coast for the very last bit. Once in the shed, power is provided from power leads in the ceiling, which are plugged into the side. It is absolutely imperative that these are all removed before the train leaves the shed, or very bad things happen. For more info see this link: www.districtdave.co.uk/html/current_supply.htmlI'm not actually sure how the train gets out of the shed after the power leads have been removed, but it will be drawn forward slightly so that the front car is on juice. The video you refer to was filmed as part of the filming for a training DVD. It was intended to show the move from West Kensington back to Barons Court, but there was disruption and it ended up going to High Street Ken. See this post for more. |
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Post by Deleted on Sept 28, 2016 20:39:59 GMT
Hmmm. All very interesting, thank you. Also, I viewed the suggested links.
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rincew1nd
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Post by rincew1nd on Sept 28, 2016 20:46:53 GMT
There's a similar video, a little old now of the 38ts entering the Acton depot of the LT Museum: The blurb states: How they get it out of the depot I'm less sure as whenever I've been there I've never seen any Shed Lead; perhaps number35 could enlighten us? |
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Post by PiccNT on Sept 28, 2016 21:21:25 GMT
When we take trains into Northfields Depot from the east end, we are normally instructed to leave the train "back end on". The rear cab door is lined up with the loading platform just by the walk boards. We do this both when stabling the train at night or reversing during the day. We do get an "MA Lost" audible warning about the then back end of the train being off juice when we are preparing to take the train back out.
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Post by Deleted on Sept 28, 2016 21:53:59 GMT
When we take trains into Northfields Depot from the east end, we are normally instructed to leave the train "back end on". The rear cab door is lined up with the loading platform just by the walk boards. We do this both when stabling the train at night or reversing during the day. We do get an "MA Lost" audible warning about the then back end of the train being off juice when we are preparing to take the train back out. How do you know where to stop? |
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Post by version3point1 on Sept 28, 2016 22:54:01 GMT
When we take trains into Northfields Depot from the east end, we are normally instructed to leave the train "back end on". The rear cab door is lined up with the loading platform just by the walk boards. We do this both when stabling the train at night or reversing during the day. We do get an "MA Lost" audible warning about the then back end of the train being off juice when we are preparing to take the train back out. How do you know where to stop? There used to be shunters marks painted on the floor which indicate you being "back end on". You can see an example of said marker here (it's like a triangle): www.flickr.com/photos/fish7373/19948738888/You'd park it anywhere around, on or before there. It's also where we would hand over to a shunter to take us through the sheds if for whatever reason we had to go through to Boston end (which was what would sometimes happen during engineering works when we were shut east Acton/Northfields), as line drivers aren't permitted to drive through. That said – nine times out of ten, I just used to line it up with the train next door.  Once in the shed, power is provided from power leads in the ceiling, which are plugged into the side. It is absolutely imperative that these are all removed before the train leaves the shed, or very bad things happen. It depends how far you get. It's easily done if you forget to check, but the CDU will start shouting with 'MOTORING ON SHED PLUG' illuminated, and the shunter would most likely notice and hear the unit that the leads feed into being pulled along its guide rails and flag you down. Though there are stories of people having left Northfields with bits of the roof attached to the train.. I'm not actually sure how the train gets out of the shed after the power leads have been removed, but it will be drawn forward slightly so that the front car is on juice. This is what's known as "railing" a train, but yes, the train is normally put in a place where it can then draw current of its own accord and keep things ticking over (like the compressors), so normally a car. |
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Post by Deleted on Sept 29, 2016 3:13:25 GMT
Does that mean compressors won't run in the other 3-car set, while the train is situated as described with one third rail shoe making contact? If so, would that eventually set the brakes on those other cars?
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Post by Dstock7080 on Sept 29, 2016 4:18:37 GMT
Does that mean compressors won't run in the other 3-car set, while the train is situated as described with one third rail shoe making contact? If so, would that eventually set the brakes on those other cars? Indeed the compressor wouldn't run on the unit without traction current but main-line air is continuous throughout the train, so will be fed by the remaining compressor. |
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Post by up1989 on Oct 17, 2016 21:10:11 GMT
On the Northen when stabling we get told '6 Car mark' and there is either a 6 dangling from the roof or a stopping diamond.
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Post by number35 on Feb 18, 2017 9:50:16 GMT
There's a similar video, a little old now of the 38ts entering the Acton depot of the LT Museum: The blurb states: How they get it out of the depot I'm less sure as whenever I've been there I've never seen any Shed Lead; perhaps number35 could enlighten us? |
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Post by number35 on Feb 18, 2017 10:15:09 GMT
There's a similar video, a little old now of the 38ts entering the Acton depot of the LT Museum: The blurb states: How they get it out of the depot I'm less sure as whenever I've been there I've never seen any Shed Lead; perhaps number35 could enlighten us? |
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Post by Deleted on Feb 18, 2017 10:17:55 GMT
I am pretty sure its done the same way its done at acton works, and its dragged out by battery operated vehicle.
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Post by number35 on Feb 18, 2017 10:23:36 GMT
Hi Rincew1nd
Sorry I don't think my last two attempts to post worked - third time lucky hopefully.
You are quite right - the LTM Depot doesn't have traction leads to power up the 38 stock. It's now a store rather than a maintenance depot so we can't really have such things in a place which we open to the public. Our Depot roads don't have inspection pits either so we are able to use an approved method involving a fork lift and scotching to push the 38 out to a point where it can pick up traction current. You may remember the two shunting unimogs at Lillie Bridge which did a similar thing in that they were using rubber tyre to move stock.
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