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Post by Deleted on Jul 4, 2012 23:38:39 GMT
Good Evening everyone!
When I came to London yesteryear, I noticed something strange... at least for me...
When I was on the District Line, and other as well, I noted that in the middle of the consists there were driving units. I came to a conclusion some time after that these kind of formations are common in the Underground, but can't find myself a reason for such!
Why are driving units in the middle of complete consists? Are theses cabs ridable or are they disassembled?
Oh, and I'm sorry if this question was already made by someone! Sometimes we call things by different names and searches won't work at all.
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Post by Deleted on Jul 5, 2012 9:56:41 GMT
The provision of double-ended D stock units was for uncoupling - long since forgotten about! That's why we now see no new double enders.
A stock (what's left of the fleet) are all formed DM-T-T-DM as a unit, although some cabs are not equipped for being driven forwards in passenger service (the white cabs)
C stock are formed DM-T as a unit, and hence all C stock trains will have a cab facing a car end window (which looks rather odd from inside the trailer)
D stock have a mix of DM-T-UNDM and DM-T-DM formation units.
72 stock are almost all formed DM-T-T-DM+UNDM-T-DM, except for just one train, formed DM-T-T-UNDM+UNDM-T-DM.
73 stock again are a mix of DM-T-DM and DM-T-UNDM sets.
92 stock also display this as their units are formed DM-UNDM and UNDM-UNDM. I believe there are not enough UNDM-UNDM sets to make the entire fleet and hence there are several trains running about with a middle DM in the formation - also many of these cabs have had spares pinched. Of course you won't see that on the Drain as they are only formed as 4 car trains and hence have to be DM-UNDM+UNDM-DM!
95 and 96 stock are formed with no middle cabs, all units carry a UNDM, the same as 2009 stock except these have a semi-permanent bar across the two rather than the usual wedgelock! S stock are also formed of two units, not quite as sure on the coupling inbetween the units on these.
For the record:
DM - Driving Motor
T - Trailer
UNDM - Uncoupling Non Driving Motor (has a small shunt driving panel hidden at the coupler end of the car for shunting)
- is a coupling between cars in a unit, and + is a coupling between units.
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Phil
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Post by Phil on Jul 5, 2012 10:54:45 GMT
Yes - in those days the idea was, that if a train became defective, just the half that was defective could be removed and another good 'half' attached.
Obviously, since on a given train either half could be the defective one, the spare 'halves' needed to be able to couple at either end, so themselves needed a cab at both ends.
Since then it has been considered cheaper to keep no spare 'halves' (double ended units) and instead treat each train as a single 6- or 7-car unit. So if one car becomes defective the whole train is out of service till it's fixed........
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North End
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Post by North End on Jul 5, 2012 13:52:49 GMT
Yes - in those days the idea was, that if a train became defective, just the half that was defective could be removed and another good 'half' attached. Obviously, since on a given train either half could be the defective one, the spare 'halves' needed to be able to couple at either end, so themselves needed a cab at both ends. Since then it has been considered cheaper to keep no spare 'halves' (double ended units) and instead treat each train as a single 6- or 7-car unit. So if one car becomes defective the whole train is out of service till it's fixed........ To be fair, the modular design of modern trains does lend itself to this approach. Speaking for the 95 stock on which I am most familiar, most trains that go to depot with defects simply return a report - "XXX changed". The defective item will be replaced with a good one from stores, and will then be sent away for investigation. Only for more serious defects or those involving more than one car will a train be out of service for longer than a day or two. It is interesting that the Northern Line generally keeps the 95 stock trains in their as-delivered formations. It is very rare for mis-formed trains to appear on the Northern Line. However, the similar trains on the Jubilee Line get changed around regularly. |
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Post by Deleted on Jul 5, 2012 14:41:29 GMT
So, is it true to say that middle cabs are like shunting cabs when parts of the whole train are separated? If that is the case, it means that DM-T cannot be separated that easily, that is, you can't take of only one carriage and put another one in its place like a normal train?
And the S Stock, since it isn't a Jacob bogie unit, can't the carriages be separated the same way has the ICE3? (Each car has a Scharfenberg couple that can be uncloupled if needed to send a single car to the workshop)
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Colin
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Post by Colin on Jul 5, 2012 17:29:31 GMT
The provision of double-ended D stock units was for uncoupling - long since forgotten about! That's why we now see no new double enders. Uncoupling stopped long before D stock was born!! As Phil said, the double enders were for maintenance purposes. So, is it true to say that middle cabs are like shunting cabs when parts of the whole train are separated? If that is the case, it means that DM-T cannot be separated that easily, that is, you can't take of only one carriage and put another one in its place like a normal train? A train is made up of two, three or four units. A unit is two, three or four cars that are permanently coupled together with a bar. Two car units only have one driving cab; some three & four car units are double ended (driving cab at each end). All units with a cab at one end will have a basic driving position at the other end for shunting purposes - the shunting position isn't usually obvious whilst the train is in passenger service......A stock is perhaps the exception as their shunting positions are former driving cabs. And the S Stock, since it isn't a Jacob bogie unit, can't the carriages be separated the same way has the ICE3? (Each car has a Scharfenberg couple that can be uncloupled if needed to send a single car to the workshop) The S8's are made up of two 4 car units and the S7's are made up of one four car unit and one three car unit. I don't know the actual coupling arrangements but I seem to recall that they are "semi permanently" coupled. |
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Post by Deleted on Jul 5, 2012 17:33:32 GMT
I was under the impression that the original plan at D stock introduction was to run a 6 car train and split at Chiswick Park to go towards Richmond and Ealing Broadway as 3 car units. Don't know how true that is, though... S stock are semi-permanent between cars and I assume they are between units as well, though I've heard that they have wedgelocks. This is where we need PRJB  |
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Post by Dstock7080 on Jul 5, 2012 18:36:02 GMT
I was under the impression that the original plan at D stock introduction was to run a 6 car train and split at Chiswick Park to go towards Richmond and Ealing Broadway as 3 car units. Don't know how true that is, though... Good plan! for the first 10 trains to arrive at Turnham Green; would've been interesting to see the next arrivals driving from the UNDM with no window or seat for the Driver! |
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Post by t697 on Jul 5, 2012 18:47:01 GMT
I was under the impression that the original plan at D stock introduction was to run a 6 car train and split at Chiswick Park to go towards Richmond and Ealing Broadway as 3 car units. Don't know how true that is, though... S stock are semi-permanent between cars and I assume they are between units as well, though I've heard that they have wedgelocks. This is where we need PRJB By the time 1973TS and D78 were specified and designed, it was decided only to have a few Double-ended Units, to provide some flexibility in depots for when by chance there were defects on several units all say 'A' enders (or all 'D'). The double-enders allow full trains to be made up, while minimising overall for the fleet the waste of passenger space of a middle cab. I'm certain there was no plan to divide District line trains in service at Turnham Green or anywhere else. S stock have mechanical only wedglocks at the outer ends only. There is no real operational concept of a 'unit' within an S stock train and they are semi-permanently coupled throughout. |
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metman
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Post by metman on Jul 5, 2012 19:09:27 GMT
The provision of double-ended D stock units was for uncoupling - long since forgotten about! That's why we now see no new double enders. A stock (what's left of the fleet) are all formed DM-T-T-DM as a unit, although some cabs are not equipped for being driven forwards in passenger service (the white cabs) C stock are formed DM-T as a unit, and hence all C stock trains will have a cab facing a car end window (which looks rather odd from inside the trailer) D stock have a mix of DM-T-UNDM and DM-T-DM formation units. 72 stock are almost all formed DM-T-T-DM+UNDM-T-DM, except for just one train, formed DM-T-T-UNDM+UNDM-T-DM. 73 stock again are a mix of DM-T-DM and DM-T-UNDM sets. 92 stock also display this as their units are formed DM-UNDM and UNDM-UNDM. I believe there are not enough UNDM-UNDM sets to make the entire fleet and hence there are several trains running about with a middle DM in the formation - also many of these cabs have had spares pinched. Of course you won't see that on the Drain as they are only formed as 4 car trains and hence have to be DM-UNDM+UNDM-DM! 95 and 96 stock are formed with no middle cabs, all units carry a UNDM, the same as 2009 stock except these have a semi-permanent bar across the two rather than the usual wedgelock! S stock are also formed of two units, not quite as sure on the coupling inbetween the units on these. For the record: DM - Driving Motor T - Trailer UNDM - Uncoupling Non Driving Motor (has a small shunt driving panel hidden at the coupler end of the car for shunting) - is a coupling between cars in a unit, and + is a coupling between units. The only units which were regularly uncoupled in service were the A stock and this stopped in 1981. The D and 1973 stocks were indeed provided with some double cab units for flexibility. The 1973 stock was able to run on the Aldwych shuttle rather than retain a 1962 set. The D stock was also able to operate in 3 car trains on the East London line whilst the A stock were converted to OPO. I believe the 2009 stock actually has a coupling point like the 1995/6 stock. Finally, the 1972 stock is provided with middle cabs to aid coupling after being turned on the Kennington loop of the Northern line (the mk2 stock started on the Northern too!). |
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Post by norbitonflyer on Jul 5, 2012 19:31:47 GMT
The only units which were regularly uncoupled in service were the A stock and this stopped in 1981. Qualified - "The only units still in service which were......." The District regularly ran 6car formations boosted to eight in the peaks, and the R stock as delivered had 4-car east end and 2-car west end unkits for that reason - a second west end unit being added when required. Later, when uncoupling was abolished, 7-car trains were formed, by transferring a NDM from one 4 car set to another, to make a five and a three, which ran with one or two 2car sets respectively. Middle driving cabs are occasionally seen on the Central Line - there is a small excess of cabbed units over non-cabbed units, for operational flexibility. (A train can run with three cabs, or even four, but not with only one) When the bakerloo ran to Watford Junction, one could occasionally see an empty unit led by an UNDM being driven on a passenger-carrying line all the way to Croxley Green depot, about a mile! |
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Post by astock5000 on Jul 5, 2012 20:50:10 GMT
I believe the 2009 stock actually has a coupling point like the 1995/6 stock. They do have a wiper and a headlight, and there doesn't seem to be much point in fitting that if they are permanently coupled. However I found a photo of one on the internet and it doesn't look like it has an automatic coupler. |
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Post by Dstock7080 on Jul 5, 2012 21:05:28 GMT
The District regularly ran 6car formations boosted to eight in the peaks, and the R stock as delivered had 4-car east end and 2-car west end unkits for that reason - a second west end unit being added when required. Later, when uncoupling was abolished, 7-car trains were formed, by transferring a NDM from one 4 car set to another, to make a five and a three, which ran with one or two 2car sets respectively. Probably a slip of the pen/finger(!) but you got the R Stock ends mixed up, 2-car units were at the east-end, the 5/4/3-cars being at the west. |
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Post by Deleted on Jul 5, 2012 21:53:56 GMT
The datasheets given out on the 1967 stock First and Last tour last year for the 2009 stock (yes, they gave us 67s too) state that it's a bar. I meant Turnham Green earlier, map confusion  |
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Post by Deleted on Jul 11, 2012 22:36:11 GMT
I believe the 2009 stock actually has a coupling point like the 1995/6 stock. They do have a wiper and a headlight, and there doesn't seem to be much point in fitting that if they are permanently coupled. However I found a photo of one on the internet and it doesn't look like it has an automatic coupler. Can't for the life of me think of the proper term for it, but between 2 09 Stock units there is a semi permanent bar coupler. The difference being you undo a couple of swing bolts, rather than 10-15 bolts around the flange like on the other intermediate couplers. The only thing they are intended to split for is to go on the lathe, which is for four cars only. |
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Post by Deleted on Jul 11, 2012 23:08:30 GMT
Can't for the life of me think of the proper term for it, but between 2 09 Stock units there is a semi permanent bar coupler. The difference being you undo a couple of swing bolts, rather than 10-15 bolts around the flange like on the other intermediate couplers. The only thing they are intended to split for is to go on the lathe, which is for four cars only. Is that why between the 4th and 5th cars on the 09 stock there are 'windscreen' wipers on the windows at the end of the cars? I'd always wondered what they were for! |
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Post by rsdworker on Jul 12, 2012 1:59:57 GMT
shunting mode cabinet located there i believe = simllar to central line - they have shunting cabinet area
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Post by Deleted on Jul 12, 2012 16:42:42 GMT
So in case of a failure on the southern unit in one train and the northern in another on the Victoria, they won't couple the working two units together to work as one train?
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Post by Deleted on Jul 12, 2012 21:48:54 GMT
So in case of a failure on the southern unit in one train and the northern in another on the Victoria, they won't couple the working two units together to work as one train? No they are intended to stay as fixed 8 car consists. That's not to say it will never happen though! And rsdworker, there is a shunting console that plugs in under the perch seat at the D end of the 4th and 5th cars. |
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Post by tubeprune on Jul 19, 2012 7:15:59 GMT
So in case of a failure on the southern unit in one train and the northern in another on the Victoria, they won't couple the working two units together to work as one train? No they are intended to stay as fixed 8 car consists. That's not to say it will never happen though! And rsdworker, there is a shunting console that plugs in under the perch seat at the D end of the 4th and 5th cars. I'd like to see a photo of that in place. I'm wondering how the T/O holds the control unit while the train is moving. Or, does the console sit somewhere secure? Then, how does the unit uncouple? I thought the couplers were bolted. I remember they were called "muff couplers" originally. You'd need a pit to undo them, wouldn't you? All sounds a bit of a palava to me. I'll bet they don't do it too often. Thinking on a bit, they will have to do it if they want to lift a unit because the lifting shop at NPK is only long enough for a 4-car. Wouldn't a tug be better than the control unit? It would save all the trouble with leads. They can't have made it that difficult, surely? I must have missed something  |
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Post by Deleted on Jul 19, 2012 21:33:06 GMT
I'd like to see a photo of that in place. I'm wondering how the T/O holds the control unit while the train is moving. Or, does the console sit somewhere secure? Then, how does the unit uncouple? I thought the couplers were bolted. I remember they were called "muff couplers" originally. You'd need a pit to undo them, wouldn't you? All sounds a bit of a palava to me. I'll bet they don't do it too often. Thinking on a bit, they will have to do it if they want to lift a unit because the lifting shop at NPK is only long enough for a 4-car. Wouldn't a tug be better than the control unit? It would save all the trouble with leads. They can't have made it that difficult, surely? I must have missed something It mounts to where the perch seat is, fairly solidly. The coupler just has a couple of swing bolts - not the muff coupler you remember. They have an 8 car lift at NPK, so don't need to split for that purpose. |
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Post by tubeprune on Jul 21, 2012 7:00:49 GMT
They have an 8 car lift at NPK, so don't need to split for that purpose. Oh, OK. That's what I missed! Which road is it on? |
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Post by Deleted on Jul 21, 2012 10:46:16 GMT
They have an 8 car lift at NPK, so don't need to split for that purpose. Oh, OK. That's what I missed! Which road is it on? Cant remember the number - one on the right as you look at the front of the lifting shop |
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Post by seaeagle on Jul 29, 2012 14:04:56 GMT
And rsdworker, there is a shunting console that plugs in under the perch seat at the D end of the 4th and 5th cars. I'd like to see a photo of that in place. This is about the best picture I have of the shunting console, this is on the original train 1. www.flickr.com/photos/seaeagle47002/5840454048/in/photostream |
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Post by seaeagle on Jul 29, 2012 14:05:27 GMT
Oh, OK. That's what I missed! Which road is it on? Cant remember the number - one on the right as you look at the front of the lifting shop 38 Road. |
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