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Post by d7666 on Aug 13, 2019 12:29:27 GMT
Willesden Junction bay platform question.
The bay road track was completely relaid - not very recently, it might a couple of years now - but why does it have negative and positive conductor rails :
[1] it is too short for a Bakerloo line train
[2] the are no trainsstops, not on the starter signal nor TETS nor fixed trainstops at the stop blocks end. The lack of trainstops suggests to me it can't be used (well not normally anyway) by any running LU train, including engineers trains.
The positive rail looks to be new rail stock but completely unused well rusty. It also has nice gaps around TPWS grids. So someone has put much work into installing it.
If LU trains can't use it, why does it have 3rd and 4th rail conductor rails ? (Obviously it has negative rail for 378s.)
Is it for some kind of immunisation or earth detection or something that needs a conductor there but not for trains ?
--
Nick
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Post by Dstock7080 on Aug 13, 2019 14:02:37 GMT
Willesden Junction bay platform question. The positive rail looks to be new rail stock but completely unused well rusty. It also has nice gaps around TPWS grids. So someone has put much work into installing it. If LU trains can't use it, why does it have 3rd and 4th rail conductor rails ? (Obviously it has negative rail for 378s.) -- Nick Think you have your positives and negatives mixed up? The (centre) negative rail would have gaps cut in for TPWS grids and 378s do not require a separate negative rail, they return the positive current (outside rail) back via the running rails. |
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Post by d7666 on Aug 13, 2019 16:12:05 GMT
Willesden Junction bay platform question. The positive rail looks to be new rail stock but completely unused well rusty. It also has nice gaps around TPWS grids. So someone has put much work into installing it. If LU trains can't use it, why does it have 3rd and 4th rail conductor rails ? (Obviously it has negative rail for 378s.) -- Nick Think you have your positives and negatives mixed up? The (centre) negative rail would have gaps cut in for TPWS grids and 378s do not require a separate negative rail, they return the positive current (outside rail) back via the running rails. oops good job I'm not track trained at any level isn't it !!!! the question remains though...... let's simplify it, why has Willesden Junction bay road got 3rd and 4th rails ? |
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Post by phil on Aug 13, 2019 21:15:31 GMT
Think you have your positives and negatives mixed up? The (centre) negative rail would have gaps cut in for TPWS grids and 378s do not require a separate negative rail, they return the positive current (outside rail) back via the running rails. oops good job I'm not track trained at any level isn't it !!!! the question remains though...... let's simplify it, why has Willesden Junction bay road got 3rd and 4th rails ? You are getting yourself in a bit of a muddle over this. The outside 3rd rail is required for BOTH Underground and National Rail stock. It is charged up to either 420V positive polarity for routes only used by Underground stock, but becomes charged at 630V positive polarity for areas where both Underground and National Rail* services operate as National Rail services do not use negatively charged rails. The 4th rail is required for Underground stock ONLY and is either charged to 210V negative polarity, or it carries no charge (0V) but is connected to both running rails where both Underground and National Rail stock operate. This is because the electrical current path ALL current National Rail conductor rail powered stock use is:- substation - 3rd rail - traction motors - running rails - substation By contrast the electrical path used by ALL Underground trains is:- Substation - 3rd rail - traction motors - 4th rail - substation. As far as the bay platform at Willesden Junction is concerned then:- (1) If it is only to be used by National Rail trains then it dies not need a 4th rail** or Underground safety systems like tripcocks. It will require National Rail systems like TPWS though. (2) If it is only to be used by Underground services then it will need 4th rail and tripcocks - but not National Rail systems like TPWS. (3) If it is to be used by both Underground and National Rail services then it needs both organisations safety systems plus 4th rail. NOTE:- * London Overground services are legally part of the UKs National Rail Operation and not something TfL have the freedom to organise as they wish. ** Even if the 4th rail is not technically required for the operation of National Rail services, it can simplify maintenance or other engineering aspects to retain it - even if rack renewal has taken place. As with most railway oddities there will be a reason (though not necessarily a logical one) but such cases normally require specialist knowledge of the area concerned. |
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metman
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Post by metman on Aug 13, 2019 22:07:48 GMT
My guess and it is only a guess is that the centre negative rail is bonded to the running rails to assist with current return as it is on the rest of the section. When the track was relaid I assume there was no reason to alter this practice.
On a side note it is a pity Bakerloo Line stock cannot use the bay road but with Stonebridge Park (a regular reversing point) the next stop on there seemed little point with the expense.
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Post by superteacher on Aug 13, 2019 22:17:54 GMT
My guess and it is only a guess is that the centre negative rail is bonded to the running rails to assist with current return as it is on the rest of the section. When the track was relaid I assume there was no reason to alter this practice. On a side note it is a pity Bakerloo Line stock cannot use the bay road but with Stonebridge Park (a regular reversing point) the next stop on there seemed little point with the expense. True (even though Harlesden is between the two stations). 😀 |
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Post by philthetube on Aug 13, 2019 22:54:45 GMT
Willesden Junction bay platform question. The positive rail looks to be new rail stock but completely unused well rusty. It also has nice gaps around TPWS grids. So someone has put much work into installing it. If LU trains can't use it, why does it have 3rd and 4th rail conductor rails ? (Obviously it has negative rail for 378s.) -- Nick Think you have your positives and negatives mixed up? The (centre) negative rail would have gaps cut in for TPWS grids and 378s do not require a separate negative rail, they return the positive current (outside rail) back via the running rails. Silly but easy way the remember which rail is the positive rail, Positive is good and negative is bad, therefore trains have twice as many positives as negatives, shoes, that is. |
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DWS
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Post by DWS on Aug 14, 2019 6:35:40 GMT
The reason that Undergroud trains have more positive shoes is because the positive rail can be on the right or left side of the running rails.
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Post by phil on Aug 14, 2019 9:07:01 GMT
The reason that Undergroud trains have more positive shoes is because the positive rail can be on the right or left side of the running rails. Erm.... the same applies to National Rail |
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Post by superteacher on Aug 14, 2019 9:13:54 GMT
The reason that Undergroud trains have more positive shoes is because the positive rail can be on the right or left side of the running rails. Erm.... the same applies to National Rail Yes but surely NR trains don’t have negative shoes, which was the point being made. |
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Post by kesmet on Aug 14, 2019 23:07:17 GMT
The Bakerloo did operate for a time with the polarity reversed (according to Clive's Underground Lines Guide - anyone have any other sources for this?).
On the original subject, I'm actually surprised at the lack of train stops in the bay. So let's expand the question a bit, and ask - what protections exist on the DC line to ensure that Bakerloo and NR stocks don't come into conflict?
And a thought occurs - is the bay long enough for a four-car Bakerloo unit? Could that be used there?
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Post by Chris L on Aug 15, 2019 0:29:27 GMT
The Bakerloo did operate for a time with the polarity reversed (according to Clive's Underground Lines Guide - anyone have any other sources for this?). On the original subject, I'm actually surprised at the lack of train stops in the bay. So let's expand the question a bit, and ask - what protections exist on the DC line to ensure that Bakerloo and NR stocks don't come into conflict? And a thought occurs - is the bay long enough for a four-car Bakerloo unit? Could that be used there? There was contact many years ago. A collision happened. |
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gantshill
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Post by gantshill on Aug 15, 2019 6:21:18 GMT
The Bakerloo did operate for a time with the polarity reversed (according to Clive's Underground Lines Guide - anyone have any other sources for this?). I am sure that I first read about the reversed polarity in JR Day's The Story of London's Underground and/or Charles E Lee The Bakerloo Line - a Brief History. I probably bought the latter book in the LT Shop in Griffin House close to Edgware Road station. Much of my pocket money was spent there. But this is off-topic. |
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rincew1nd
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Post by rincew1nd on Aug 15, 2019 7:13:28 GMT
Isn't there one short 72ts set, when marshalled in a conventional set it's noticeable as there's a red fronted cab in the middle of the set.
Would that fit in the bay?
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Post by Dstock7080 on Aug 15, 2019 10:01:50 GMT
The Bakerloo Line Supplement to the Rule Book and infrastructure diagrams show Willesden Junction bay as “un-electrified track”
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Post by goldenarrow on Aug 15, 2019 10:27:43 GMT
I know that the signal protecting the SB turnout through Queens Park North Shed is interlocked to only clear when current is being drawn from the negative rail. Route learning videos from a few years back state that drivers must not accept a signal showing B on the route indicator (for the bay platform) suggesting that there is no such protection for signal WS21.
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PGtrips
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Post by PGtrips on Aug 15, 2019 12:36:53 GMT
Don't forget that the whole of the LNWR/NLL electrification was originally 4 rail, and extended onto the West London Line and thence the District to Earls Court, and the LNWR operated a through service there up to WW2 using its own stock. The then BR-only bits were converted to 3 rail in the late 60s once all the pre-war units were withdrawn. So Willesden bay is probably an anomaly as a result of this process.
As a matter of interest, can Harrow & Wealdstone reversing siding be used by NR trains?
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Post by superteacher on Aug 15, 2019 12:46:09 GMT
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Post by d7666 on Aug 15, 2019 17:21:10 GMT
My guess and it is only a guess is that the centre negative rail is bonded to the running rails to assist with current return as it is on the rest of the section. When the track was relaid I assume there was no reason to alter this practice. On a side note it is a pity Bakerloo Line stock cannot use the bay road but with Stonebridge Park (a regular reversing point) the next stop on there seemed little point with the expense. This seems most logical to me too, but it must have cost a bit to simply just not alter it. |
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DWS
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Post by DWS on Aug 17, 2019 19:02:57 GMT
The Bakerloo did operate for a time with the polarity reversed (according to Clive's Underground Lines Guide - anyone have any other sources for this?). On the original subject, I'm actually surprised at the lack of train stops in the bay. So let's expand the question a bit, and ask - what protections exist on the DC line to ensure that Bakerloo and NR stocks don't come into conflict? And a thought occurs - is the bay long enough for a four-car Bakerloo unit? Could that be used there? There was contact many years ago. A collision happened. I think that was when BR train had passed a signal at danger under rule, and failed to stop before it crashed into a Bakerloo Line Train . |
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Post by phil on Aug 17, 2019 19:44:56 GMT
On the original subject, I'm actually surprised at the lack of train stops in the bay. So let's expand the question a bit, and ask - what protections exist on the DC line to ensure that Bakerloo and NR stocks don't come into conflict? Previously both the National Rail stock that usually* worked the DC lines and the Bakerloo stock had tripcocks. These days it may be that National rail stock has migrated to TPWS as SPAD / overspeed protection while tripcocks have been retained to perform the same function for Underground stock. Given both protection systems are derived from the same overall signalling system then conflict prevention is maintained even though the actual delivery is different. * I understand that in the past when the WCML proper was shut south of Watford, British Rail did occasionally use the DC lines to carry diverted WCML traffic (diesel hauled obviously) |
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towerman
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Post by towerman on Aug 23, 2019 12:31:10 GMT
When I worked at Stonebridge Pk Depot from 95 to 98 I'm sure I've seen Cl313s use the bay road at Willesden Junc.
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Post by JR 15secs on Aug 23, 2019 17:09:41 GMT
When I worked at Stonebridge Pk Depot from 95 to 98 I'm sure I've seen Cl313s use the bay road at Willesden Junc. You worked with Danny & Bruce Depot Duty Managers (DDMs) then. |
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Post by d7666 on Aug 24, 2019 13:36:40 GMT
When I worked at Stonebridge Pk Depot from 95 to 98 I'm sure I've seen Cl313s use the bay road at Willesden Junc. Yes 313s did. It was often used on Sundays for engineering works timetables, on those occasions I did it, it was always NLL diversions, either immediately off NLL from Kendal Rise direction, or, different dates, off the DC route and Camden Road Primrose Hill diversion. All some while ago though, not even in 313s latter days. |
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Post by d7666 on Aug 24, 2019 13:44:23 GMT
On the original subject, I'm actually surprised at the lack of train stops in the bay. So let's expand the question a bit, and ask - what protections exist on the DC line to ensure that Bakerloo and NR stocks don't come into conflict? Previously both the National Rail stock that usually* worked the DC lines and the Bakerloo stock had tripcocks. These days it may be that National rail stock has migrated to TPWS as SPAD / overspeed protection while tripcocks have been retained to perform the same function for Underground stock. Given both protection systems are derived from the same overall signalling system then conflict prevention is maintained even though the actual delivery is different. * I understand that in the past when the WCML proper was shut south of Watford, British Rail did occasionally use the DC lines to carry diverted WCML traffic (diesel hauled obviously) On that diversion I think rarely is a better term than occasionally, it was exceedingly rare. To my knowledge there was only one piece of engineering work that caused it to be so used by a handful of trains all 47 hauled/dragged, although IIRC that work was over a very small number of consecutive weekends, not one weekend. I never did it, despite at the time taking big interest in any WCML diversion. I can't now recall what the work was nor the dates, but it was certainly the 47s era, not 25s/31s era with Stonebridge crews that did not know 47s but had in older days handled all such London area work. I am not aware of any emergency diversions over that route although no doubt there may have been. |
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Post by metrailway on Aug 24, 2019 14:43:28 GMT
The Bakerloo Line Supplement to the Rule Book and infrastructure diagrams show Willesden Junction bay as “un-electrified track” The bay is definitely electrified. During engineering works on the North London Line, the bay is used for running diversionary Willesden Junction (LL) to Stratford via Primrose Hill services. |
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Post by superteacher on Aug 24, 2019 16:25:08 GMT
It’s also used to terminate late running trains which were heading to Richmond or Clapham Junction.
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towerman
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Post by towerman on Aug 30, 2019 13:43:33 GMT
When I worked at Stonebridge Pk Depot from 95 to 98 I'm sure I've seen Cl313s use the bay road at Willesden Junc. You worked with Danny & Bruce Depot Duty Managers (DDMs) then. Yeah,I was on Bruce's shift.Danny I knew before from The Victoria Line.I think Danny's retired now. |
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metman
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Post by metman on Aug 30, 2019 17:52:23 GMT
I’ve seen class 172s use the middle bay - I believe there were a few starters to Gospel Oak from there.
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roythebus
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Post by roythebus on Aug 30, 2019 21:39:46 GMT
Willesden bay is electrified, there's been a train stabled there every weekend during the WJ-Camden Road closures.
In the early 1970s Stonebridge men had the 25 as basic diesel, along with the 08 and class 81-87. 47s were a rarity on the WCML at that time. It was not until the scrapping of the class 25s that 31s became more common.
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