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Changing Power 11/05/2014 at 00:12 #60312 | |
Danny252
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Quick one this time - is it possible for a train to change power without a Next command? I.e. can I bring a train in as 3DC, then stop it at a location with both 3DC and AC supplied, and then send it off down an AC line on the same Timetable? I've not yet been able to convince a train to raise its pantograph without a TT change, but perhaps it's possible.
Last edited: 11/05/2014 at 00:12 by Danny252 Log in to reply |
Changing Power 11/05/2014 at 02:00 #60317 | |
BarryM
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What happens if you set the train's Power Types to Overhead and 3rd rail? Barry Barry, Sydney, New South Wales, Australia Log in to reply |
Changing Power 11/05/2014 at 02:38 #60318 | |
mfcooper
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The train in your scenario must have both conductor shoes and a pantograph. Therefore, the train always has both AC and 3DC capabilities. You don't need to change the traction type selected for the train to keep moving, you just need to set it up with both traction types.
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Changing Power 11/05/2014 at 09:55 #60322 | |
jc92
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" said:The train in your scenario must have both conductor shoes and a pantograph. Therefore, the train always has both AC and 3DC capabilities. You don't need to change the traction type selected for the train to keep moving, you just need to set it up with both traction types.however in that case it would need to stop to raise/lower the pantograph. I wonder what would happen if you set a Thameslink train a passing time at Farringdon? (apart from losing its pantograph as per the recent incident :P) "We don't stop camborne wednesdays" Log in to reply |
Changing Power 11/05/2014 at 10:32 #60324 | |
58050
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Using Farringdon as an example as in the West Hampstead sim you set both power types in the train types folder to both AC/3DC. But the train whether it is booked to stop at Farringdon or not will stop to raise or drop the pantograph so the alternate power supply then powers the traction unit. I think the only time it can be done withour stopping is in the case of Cl.73 electro diesels where if the loco is running on diesel the shoes can be dropped to pick up the DC traction supply, but whther the loco has to be stationary for this to happen I can't confirm. I'm sure 'Crompton' would be able to give a more precise answer on that, but whenever I've spoken to Hither Green men in the past they've never mentioned you have to stop. There is a split second when changing from AC to DC or DC to AC when the unit is 'dead' before the electrical power system kicks in again running off the alternative source.
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Changing Power 11/05/2014 at 11:00 #60325 | |
Finger
![]() 220 posts |
" said:" said:Seriously, why? Can't your trains (and drivers) lower pantographs on the fly like in this video)?The train in your scenario must have both conductor shoes and a pantograph. Therefore, the train always has both AC and 3DC capabilities. You don't need to change the traction type selected for the train to keep moving, you just need to set it up with both traction types.however in that case it would need to stop to raise/lower the pantograph. [video width=800 height=450 type=youtube]Xb4wUrq55aU[/video] Returning to the original topic though - While it is certainly possible to create trains that have two power sources in SimSig, it is not possible to create trains which behave differently on different power systems (eg. differential maximal speeds when running on diesel/25 kV). Also, trains that have different maximal speeds over parts of their journey are almost impossible to create and even then have to stop when their maximal speed changes. The Cambridge 1985 timetable contains such trains, but they don't work as intended. Still, I don't think this problem is very serious, I'd say there are better possible improvements to SimSig. Log in to reply |
Changing Power 11/05/2014 at 11:02 #60326 | |
Danny252
![]() 1461 posts |
" said:The train in your scenario must have both conductor shoes and a pantograph. Therefore, the train always has both AC and 3DC capabilities. You don't need to change the traction type selected for the train to keep moving, you just need to set it up with both traction types.Ah, so there's no way to go from 3DC only to AC only? Righto. Last edited: 11/05/2014 at 11:02 by Danny252 Log in to reply |
Changing Power 11/05/2014 at 11:12 #60327 | |
Steamer
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" said:You can detach a 3DC loco then attach an AC loco, which would have that result. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Last edited: 11/05/2014 at 11:13 by Steamer Log in to reply |
Changing Power 11/05/2014 at 11:31 #60328 | |
Peter Bennet
![]() 5377 posts |
" said:" said:But trains don't change from DC only to AC only (unless you have a loco change as has been said) trains are otherwise fully fitted with both capabilities and swap over as required with no intervention from the signaller. Remember this is only a signalling program, not a train driving program.The train in your scenario must have both conductor shoes and a pantograph. Therefore, the train always has both AC and 3DC capabilities. You don't need to change the traction type selected for the train to keep moving, you just need to set it up with both traction types.Ah, so there's no way to go from 3DC only to AC only? Righto. If for train dynamic purposes you need train to run differently then, yes, you will have to change timetable using "next". Peter I identify as half man half biscuit - crumbs! Log in to reply |
Changing Power 11/05/2014 at 11:55 #60329 | |
Danny252
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Well, my reasoning is that the signaller shouldn't be able to try and route the train over AC-only tracks before the switchover has occurred, or over DC-only after. If that were to occur, I would indeed expect the signaller to have to intervene when the driver phones in to confirm the route and required traction power change.
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Changing Power 11/05/2014 at 12:04 #60330 | |
Steamer
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" said:Well, my reasoning is that the signaller shouldn't be able to try and route the train over AC-only tracks before the switchover has occurred, or over DC-only after. If that were to occur, I would indeed expect the signaller to have to intervene when the driver phones in to confirm the route and required traction power change.If you send the train the wrong way, the driver will phone anyway in stating wrong route. If it was the booked route, Otherwise, he'd know he was heading towards a different power supply and would change over on the dual voltage section. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
Changing Power 11/05/2014 at 12:18 #60331 | |
Sacro
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The only affect a signaller would notice (assuming the train has AC and DC support) might be the train stopping for a minute in section to change over, some trains automatically apply the brakes when they lose power (eg 377s) and need to stop, whereas some units (eg 378s) can happily switch over on the move. Maybe that could be a feature for train categories, power type change speed / time. Log in to reply |
Changing Power 11/05/2014 at 14:02 #60335 | |
mfcooper
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For the AC/DC Changeover on the West London Line, 378s can now do this on the move at a max of 25mph. However, only if they have proceed signals! Danny's point regarding wrong-routing before or after the changeover is an interesting point. Drivers are only *meant* to changeover at particular locations. Thinking back to the old North London Line layout, a driver could go non-stop from Camden Road to Dalston Kingsland via AC or DC lines, but the traction changeover locations are designed to be in certain places. A real-life driver would stop and query the route, whereas I suspect a SimSig driver would keep going because both traction types are available. Log in to reply |
Changing Power 11/05/2014 at 15:30 #60339 | |
Noisynoel
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If a train is fitted with both AC/DC then why wouldn't the signaller route it over tracks that are fitted with either. Just because a train has changed over once, doesn't mean it won't change over again, and to be honest I can't think of the top of my head anywhere where this may be an issue
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Changing Power 11/05/2014 at 16:00 #60343 | |
Sacro
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" said:If a train is fitted with both AC/DC then why wouldn't the signaller route it over tracks that are fitted with either. Just because a train has changed over once, doesn't mean it won't change over again, and to be honest I can't think of the top of my head anywhere where this may be an issuePantagraph / 3rd rail shoe failure? Also the time it takes to switch between power types could cause delays. Log in to reply |
Changing Power 11/05/2014 at 18:11 #60349 | |
Noisynoel
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No because the majority of dual power stock can in fact change over on the move
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Changing Power 11/05/2014 at 18:16 #60350 | |
Danny252
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Sounds like a risky business relying on drivers to switch over traction power whilst moving past signals at speed - do it a bit too late and all of a sudden you're in a bit of a mess! Also, going by the signs put up at locations where traction changes are normal (e.g. Camden Road), I dare say that drivers forget every once in a while, so it would be prudent to remind them before sending them off down a different route. Also, for all the talk of changing on the move, the services in question - various LO ones around Camden Jn - are all booked to stop to swap traction power. Of course, it's possible to select both power types as "initial" and just have a booked stop with no change, but that makes the "initial power" option seem quite pointless. Last edited: 11/05/2014 at 18:23 by Danny252 Log in to reply |
Changing Power 12/05/2014 at 09:30 #60372 | |
kbarber
![]() 1723 posts |
" said:Using Farringdon as an example as in the West Hampstead sim you set both power types in the train types folder to both AC/3DC. But the train whether it is booked to stop at Farringdon or not will stop to raise or drop the pantograph so the alternate power supply then powers the traction unit. I think the only time it can be done withour stopping is in the case of Cl.73 electro diesels where if the loco is running on diesel the shoes can be dropped to pick up the DC traction supply, but whther the loco has to be stationary for this to happen I can't confirm. I'm sure 'Crompton' would be able to give a more precise answer on that, but whenever I've spoken to Hither Green men in the past they've never mentioned you have to stop. There is a split second when changing from AC to DC or DC to AC when the unit is 'dead' before the electrical power system kicks in again running off the alternative source. I believe the 73s can change over on the move. When I was learning Acton Wells we had a regular MGR train from Tyne Yard to Ridham Dock; it had changed engines at Brent Junction (Midland line just north of Cricklewood) and was brought forward by a pair of 73s. I was told of an incident where they'd changed over power systems a bit early and the shoes had dropped before they were all on the juice rails. Because the line from Cricklewood wasn't electrified there were no run-on ramps from that direction, nor current rail gaps that would have allowed them to run in properly. Consequently the juice rail was knocked right off the insulating pots... Log in to reply |
Changing Power 12/05/2014 at 16:48 #60390 | |
Forest Pines
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Class 373s can certainly change over whilst moving, although I believe there was at least one let's-demolish-Sandling-footbridge incident. Not sure if any ever had their shoes knocked off heading the other way. Going slightly more off topic, all the early BR A.C. electric classes were dual voltage with automatic changeover triggered by lineside equipment, albeit with power supplied through the same pantographs onboth voltages. That was phased out after the changeover gear on the Class 303 turned out to be disastrously unreliable, causing several on-train fires. Log in to reply |
Changing Power 12/05/2014 at 17:43 #60392 | |
Peter Bennet
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" said:" said:When the 73s worked the late night/early morning newspaper+BSK trains out of the London Terminals they often started on diesel, changing to electric once the danger of gaping on the point-work had passed; or at least that's why I presume they did it.Using Farringdon as an example as in the West Hampstead sim you set both power types in the train types folder to both AC/3DC. But the train whether it is booked to stop at Farringdon or not will stop to raise or drop the pantograph so the alternate power supply then powers the traction unit. I think the only time it can be done withour stopping is in the case of Cl.73 electro diesels where if the loco is running on diesel the shoes can be dropped to pick up the DC traction supply, but whther the loco has to be stationary for this to happen I can't confirm. I'm sure 'Crompton' would be able to give a more precise answer on that, but whenever I've spoken to Hither Green men in the past they've never mentioned you have to stop. There is a split second when changing from AC to DC or DC to AC when the unit is 'dead' before the electrical power system kicks in again running off the alternative source. Peter I identify as half man half biscuit - crumbs! Log in to reply |
Changing Power 12/05/2014 at 17:58 #60393 | |
kbarber
![]() 1723 posts |
" said:Class 373s can certainly change over whilst moving, although I believe there was at least one let's-demolish-Sandling-footbridge incident. Not sure if any ever had their shoes knocked off heading the other way. There were also issues with the 3rd rail shoes. Between Coquelles and Lille there was no problem, but (as I understood it) the points machines south of Lille were different and would be foul of lowered shoes, with the likelihood of an Ealing Broadway-type derailment. During the runup to opening, there was certainly talk (maybe more) of complex infra-red detection gear at Cheriton that would sense a lowered shoe and return signals to danger before the train could cause trouble. Which, of course, led to issues of fail-safe design, reliability and any number of failure detection precautions to ensure it neither failed wrong-side nor messed up the service too badly. Personally I thought a good solid block of concrete, preferably with a thick steel leading edge, would be far more appropriate (assuming it was necessary at all). After all a few shoes knocked off has got to be better than a 373 spreading itself around the countryside at speed after points open beneath it. It would also have allowed protection at frequent intervals in case the shoes became lowered 'in flight'. I don't know quite what happened in the end but I suspect commonsense prevailed and the powers that be decided that the likelihood of failure was small enough that they didn't actually need to worry themselves about it in the real world. But I notice they removed the shoes pretty quickly once HS1 opened throughout to St Pancras! Log in to reply |
Changing Power 12/05/2014 at 22:20 #60401 | |
clive
![]() 2766 posts |
" said:I thought they removed them because it was one less piece of kit to maintain. Log in to reply |
Changing Power 12/05/2014 at 22:36 #60402 | |
clive
![]() 2766 posts |
" said:Magnets each side of the track signal the on-train equipment to lower and then re-raise the pantograph. They are still used at neutral sections. The dual-voltage equipment sensed the voltage every time the pan was raised and selected the appropriate tap on the transformer. Quote: Not so. The dual voltage lasted a long time after that. What actually happened was, over time, experience showed that the minimum safe spacing to nearby structures could be reduced and therefore it was safe to run 25 kV under some bridges that were previously thought to be too low. So over time the changeover points into Liverpool Street and Fenchurch Street moved westwards until eventually 6.25 kV was abolished, I think in the mid-80s. (I think Euston was 25 kV from the start; King's Cross certainly was.) Ah, found a 1981 book that says that Glasgow Suburban and east of Gidea Park were converted in 1979, Gidea Park to Manor Park in 1980, thence to Liverpool Street in 1981, with the Chingford, Enfield, Bishop's Stortford, Fenchurch Street to Barking, and Leigh-on-Sea to Shoeburyness sections due for conversions shortly after that. It says that the class 81 to 85 locos were dual voltage, but not the 86s and 87s. The only thing it says about units is that the 312/0s weren't but the 312s were; I'm sure that the 302s to 309s all were. Log in to reply The following users said thank you: BarryM, Finger |
Changing Power 13/05/2014 at 11:17 #60406 | |
kbarber
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" said:" said:I thought they removed them because it was one less piece of kit to maintain. Most definitely and I'm not implying the points machine issue is actually why they did it. But I'd have thought just locking them out could achieve the same result until there was an opportunity to do more at a scheduled works visit (and I have to admit I'm not aware if that is what was in fact done, in which case we'll never know). of course they did also have the experience of a decade of problem-free operation by the time HS1 opened. Log in to reply |