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Post by 35b on Dec 18, 2020 7:58:49 GMT
Will the ac train units be compatible with the dc train units? (ie: able to work together in the same train) If not, could a situation be reached whereby there are times when there is a shortage of serviceable train units which causes a cancellation (or two) from the timetable? Continuing on with the scenario (above), maybe some temporary short-length shuttle services would be operated? eh: Loughton - Epping, (Leytonstone -) Woodford - Hainault, (White City -) North Action - Ealing Broadway... ? Don't see why there should be a problem. On the Big Railway retractioned 455s work fine with original-condition 456s Judging by comments online elsewhere, drivers don’t entirely agree. |
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Post by bomo on Dec 18, 2020 16:34:55 GMT
Will the ac train units be compatible with the dc train units? (ie: able to work together in the same train) If not, could a situation be reached whereby there are times when there is a shortage of serviceable train units which causes a cancellation (or two) from the timetable? Continuing on with the scenario (above), maybe some temporary short-length shuttle services would be operated? eh: Loughton - Epping, (Leytonstone -) Woodford - Hainault, (White City -) North Action - Ealing Broadway... ? Don't see why there should be a problem. On the Big Railway retractioned 455s work fine with original-condition 456s Not really comparing like with like. Class 456 and 455 have never been the same traction wise. 456 has a GTO traction package (very similar to that on Class 319) whilst the SWR 455s were camshaft and are now IGBT. Multiple working between 456 and 455 both pre and post 455 retractioning has always been a bit of an approximation hence the comments from train crew.
A better comparison with the potential Central Line position would be pre and post retractioning 455s working together. It worked but it wasn't pretty at times.
EDIT 19/12. I realise I did norbitonflyer a bit of a disservice in that I completely overlooked the fact that 92ts is GTO now and so a mixed pre and post upgrade 92ts formation would be GTO and IGBT as is a formation of retractioned 455 plus 456. The point that they don't always play nicely together stands though.
Whilst working them together on SWR was always the plan I would expect LU to not even consider mixing pre and post. That avoids a potential set of additional complications which they'd have to spend time and money resolving and which will disappear once the last unit is converted. Probably not worth it at the best of times and certainly not in the current economic climate.
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Post by t697 on Dec 18, 2020 19:05:58 GMT
Re-tractioned Class 321s seem to work OK with the non reworked ones for Anglia.
Perhaps someone will tell us what's planned for Central line. There are other mods in their upgrade programme that I'd expect to make old and reworked incompatible.
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Post by Dstock7080 on Jan 4, 2021 12:22:06 GMT
Will the ac train units be compatible with the dc train units? (ie: able to work together in the same train) If not, could a situation be reached whereby there are times when there is a shortage of serviceable train units which causes a cancellation (or two) from the timetable? Continuing on with the scenario (above), maybe some temporary short-length shuttle services would be operated? eh: Loughton - Epping, (Leytonstone -) Woodford - Hainault, (White City -) North Action - Ealing Broadway... ? Finding the answer; AC and DC units are 'capable' of running together, however; the other mods such as data transmission upgrades and CIS displays will prevent mixed formations in passenger service (empty trains possible). |
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metman
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Post by metman on Jan 5, 2021 20:20:35 GMT
I can’t remember if previous refurbishments and upgrades allowed interworking. I seemed to think not. The A, C and D stock and 73 tube stock were all kept in complete trains from memory.
Off course it is far easier for Underground trains to be kept together as there is no longer uncoupling except for maintenance requirements whereas train lengths vary on the national rail network.
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Post by t697 on Jan 5, 2021 20:52:39 GMT
I can’t remember if previous refurbishments and upgrades allowed interworking. I seemed to think not. The A, C and D stock and 73 tube stock were all kept in complete trains from memory. Off course it is far easier for Underground trains to be kept together as there is no longer uncoupling except for maintenance requirements whereas train lengths vary on the national rail network. I think all those refurbs included at least some electrical change that meant there was an incompatibility on a few train wires. Mostly the addition or upgrade of Passenger Information Systems or the change to electrically controlled Passenger Alarms on fleets where the PEA used to vent the Train Line (Brake Pipe). |
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Post by gals on Jan 14, 2021 18:04:59 GMT
Does anyone have an update on this project please? Would’ve expected to see some of these out by now even with the delays.
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Post by Dstock7080 on Jan 14, 2021 18:54:44 GMT
Does anyone have an update on this project please? Would’ve expected to see some of these out by now even with the delays. Two units are at Bombardier Derby, one is expected back in London this month after being fitted with AC motors. These will then undertake dynamic testing Two units are at Ruislip undergoing data transmission installation, a test run was carried out a few days ago and all was successful. Units remain in Acton Works undergoing trial fitment of the LED lighting and wheelchair spaces. The new workshop to do the full refurbishment is a few months from completion in Acton Works, so hopefully a start can be made mid-year. |
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Post by stapler on Jan 18, 2021 8:37:18 GMT
Does anyone have an update on this project please? Would’ve expected to see some of these out by now even with the delays. Two units are at Bombardier Derby, one is expected back in London this month after being fitted with AC motors. These will then undertake dynamic testing Two units are at Ruislip undergoing data transmission installation, a test run was carried out a few days ago and all was successful. Units remain in Acton Works undergoing trial fitment of the LED lighting and wheelchair spaces. The new workshop to do the full refurbishment is a few months from completion in Acton Works, so hopefully a start can be made mid-year. For a non-tecchie: so the supply is taken from the Grid in AC. It goes through the substations and is rectified. It then is fed to the conductor rails as DC, and for the stock when fitted with new motors, taken through a rectifier mounted under the cars? |
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Post by Dstock7080 on Jan 18, 2021 8:57:28 GMT
For a non-tecchie: so the supply is taken from the Grid in AC. It goes through the substations and is rectified. It then is fed to the conductor rails as DC, and for the stock when fitted with new motors, taken through a rectifier mounted under the cars? That’s it exactly! 10 (non-quiz) points for you |
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Post by quex on Jan 18, 2021 10:27:15 GMT
For a non-tecchie: so the supply is taken from the Grid in AC. It goes through the substations and is rectified. It then is fed to the conductor rails as DC, and for the stock when fitted with new motors, taken through a rectifier mounted under the cars? On the train, it's fed through an inverter rather than a rectifier. A rectifier converts (typically fixed frequency) AC to DC, whereas an inverter converts DC to AC, and (depending on the specific type of control system used) allows control over the amplitude (maximum voltage) and the frequency - the combination of both typically being required for operating AC motors. |
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Post by stapler on Jan 18, 2021 13:49:06 GMT
Oh, thank you. Is an inverter kind of a rectifier back-to-front?
BTW, I gather the output from West Ham "A" power station, built by the County Borough to feed its tramways, was 2-phase .How did it get changed to 3-phase to power the trolleybuses?
Mods - sorry to digress. I should obviously have paid more attention in O Level physics!
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Post by quex on Jan 18, 2021 14:08:40 GMT
Oh, thank you. Is an inverter kind of a rectifier back-to-front? BTW, I gather the output from West Ham "A" power station, built by the County Borough to feed its tramways, was 2-phase .How did it get changed to 3-phase to power the trolleybuses? Mods - sorry to digress. I should obviously have paid more attention in O Level physics! Functionally, yes, one does the opposite of the other, and they use many of the same components. However their circuits are laid out differently - you couldn't turn a rectifier back-to-front to make an inverter. I'd love to know the answer to your West Ham question too - although as you say here isn't perhaps the best place for discussing it! |
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Post by John Tuthill on Jan 18, 2021 15:13:44 GMT
Oh, thank you. Is an inverter kind of a rectifier back-to-front? BTW, I gather the output from West Ham "A" power station, built by the County Borough to feed its tramways, was 2-phase .How did it get changed to 3-phase to power the trolleybuses? Mods - sorry to digress. I should obviously have paid more attention in O Level physics! Functionally, yes, one does the opposite of the other, and they use many of the same components. However their circuits are laid out differently - you couldn't turn a rectifier back-to-front to make an inverter. I'd love to know the answer to your West Ham question too - although as you say here isn't perhaps the best place for discussing it! The number of 'phases' would be determined by the dedicated windings on the rotor shaft? If that's the case, then the 2-phase supply would be supplying a motor? the shaft of which could be coupled to drive the shaft of a 3-phase generator? |
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Post by dm1 on Jan 20, 2021 15:10:59 GMT
Oh, thank you. Is an inverter kind of a rectifier back-to-front? BTW, I gather the output from West Ham "A" power station, built by the County Borough to feed its tramways, was 2-phase .How did it get changed to 3-phase to power the trolleybuses? Mods - sorry to digress. I should obviously have paid more attention in O Level physics! Functionally, yes, one does the opposite of the other, and they use many of the same components. However their circuits are laid out differently - you couldn't turn a rectifier back-to-front to make an inverter. Although there are many different circuits designed to act as both inverters and rectifiers - that is for example how regenerative braking works in modern rolling stock. 25kV AC (if present) gets transformed to a lower voltage and is rectified to about 750-1000V DC (if using third/fourth rail, then the DC is fed directly). That DC voltage is then fed through power electronics (effectively a fancy inverter) that nowadays generally generates a variable-frequency three-phase AC voltage that powers the motors (that would be the case on the new AC motors on the refurbished 92TS). During braking, the motor functions as generator, generating that same 3-phase voltage. The power electronics (that was acting as in inverter before) now acts as a rectifier to supply 750-100V DC again (which in third/fourth rail is fed back directly). If using 25kV AC, then this DC voltage is inverted to 25kV 50Hz and fed into the catenary. The reason for this back and forth inversion/rectification is that AC electrification uses a single phase at fixed frequency (in the UK 50Hz), whereas the AC motors need a variable frequency three-phase supply to be able to operate at different speeds efficiently. In LU world the supply is DC, but nowadays AC motors are used because they are smaller, more efficient and require less maintenance than DC motors. However they only really became practical once semiconductors and power electronics developed (earlier GTO thyristors, nowadays mostly IGBTs). So on LU you would only need DC <-> variable frequency 3-phase AC conversion. Hopefully that's a helpful (simplified) summary - it gets quite complicated quite quickly, but in short some rectifiers are also inverters, some inverters are also rectifiers, and some can only do one or the other. |
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Post by grumpycat on Mar 17, 2021 14:53:23 GMT
I know it's a bit of a thread bump but any more news on the refurb?
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Post by Dstock7080 on Mar 18, 2021 10:31:55 GMT
I know it's a bit of a thread bump but any more news on the refurb? nothing yet, still awaiting confirmation that the first two units returned safely from Derby. New workshop in Acton Works is progressing well, tracks laid and fitting out continuing. Even has a 'green roof' with plants/trees/grass growing. |
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Post by noddymac on Mar 19, 2021 0:02:36 GMT
I know it's a bit of a thread bump but any more news on the refurb? According to our staff magazine they hope to have the first train out in service by the end of this year. Time will tell whether that happens or not. |
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Post by Dstock7080 on Apr 8, 2021 11:51:29 GMT
Recent Central Line newsletter to Staff suggests that the W&C '92 Stock will have some of the CLIP work done;
no mention of where but would guess within Waterloo depot
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rincew1nd
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Post by rincew1nd on Apr 8, 2021 12:51:24 GMT
Or will they lift out and send to Acton by road?
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Post by John Tuthill on Apr 8, 2021 13:52:27 GMT
Or will they lift out and send to Acton by road? Are you serious??!! Signage and re-taping a grab pole, even a job centre reject could do that.  |
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Post by John Tuthill on Apr 8, 2021 13:57:02 GMT
Or will they lift out and send to Acton by road? Are you serious??!! Signage and re-taping a grab pole, even a job centre reject could do that. Sorry, I mis read it, thought it was wheelchair signage as well.No doubt there will be internal mods to each car, but even so if its been designed with all the relevant drawings, I see no reason why the work can't be done at Waterloo. Again my apologises for reading too fast  |
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Post by superteacher on Apr 8, 2021 18:28:53 GMT
MOD COMMENT:
The above post is a reminder as to why it’s important to think before posting.
Also, a reminder to think about the tone of our posts. I’m sure that in the current climate, there are quite a few “job centre rejects” through no fault of their own. It’s not the first time that posting tone has been mentioned either - just saying.
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Post by spsmiler on Apr 9, 2021 23:15:18 GMT
Recent Central Line newsletter to Staff suggests that the W&C '92 Stock will have some of the CLIP work done; no mention of where but would guess within Waterloo depot Does Waterloo depot have the required equipment to install wheelchair bay? Oh and if the works are done here will the wheelchair bays be identical to the Central line fleet? |
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Post by Chris M on Apr 10, 2021 1:20:48 GMT
Does Waterloo depot have the required equipment to install wheelchair bay? That depends what equipment is needed, but as a wheelchair bay is mainly floor space and re-arranging other things inside the car, I would be surprised if there was any equipment required that they either do not already have or which cannot be easily acquired. Certainly I can't imagine it requiring something that would make winching the trains out and back in again the easier option. |
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Post by t697 on Apr 10, 2021 16:54:12 GMT
Accommodating the additional staff and welfare facilities at site might be the most difficult part.
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Post by Dstock7080 on Apr 13, 2021 14:54:45 GMT
A little bit of progress, cars 91111 92111 92446 93446 have returned to Ruislip from Derby by road today.
They will now undertake testing on LU after the dynamic testing at Derby, including running mixed trains of 1xAC/2xDC 2xAC/1xDC etc
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Post by Chris L on Apr 13, 2021 17:33:34 GMT
Accommodating the additional staff and welfare facilities at site might be the most difficult part. Temporary cabins at surface level should be possible. |
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jimbo
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Post by jimbo on Apr 13, 2021 19:51:39 GMT
Trains have been lifted in or out over a weekend in the past, but to set up for this monthly for six months, one train each time, is probably uneconomic.
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Post by grumpycat on Apr 14, 2021 12:02:49 GMT
A little bit of progress, cars 91111 92111 92446 93446 have returned to Ruislip from Derby by road today. They will now undertake testing on LU after the dynamic testing at Derby, including running mixed trains of 1xAC/2xDC 2xAC/1xDC etc ery noice cannot wait to see the test trains going past are they doing the usual mile accumulation runs? |
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