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The SprinterMeister
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« Reply #150 on: September 10, 2012, 14:02:29 » |
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Also, it's worth saying that most of these operating rules are based on a worst case scenario, i.e. during leaf-fall, and what seems perfectly possible in fine weather soon changes when conditions are different.
Quite. It has been known for 2+8 HST▸ 's to get stuck on the Devon banks with both engines running / providing full traction power in extremely poor rail conditions. The operating rules governing running them on one engine over the Devon banks are there for sound reasons based on operational experience. |
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Southern Stag
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« Reply #151 on: September 10, 2012, 14:04:31 » |
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Or do you go for say Meridians released by Midland main electrification or even more IEPs▸ .
More IEPs than specified by the DfT» is probably unlikely because of great cost of them compared to other options. |
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Louis94
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« Reply #152 on: September 12, 2012, 10:56:14 » |
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Quite. It has been known for 2+8 HST▸ 's to get stuck on the Devon banks with both engines running / providing full traction power in extremely poor rail conditions. The operating rules governing running them on one engine over the Devon banks are there for sound reasons based on operational experience.
That is very true, I have been stuck on a service going up Rattery in this situation - sparks flying from the wheels, strangely enough a service going in the other direction was in the same situation going up Hemerdon at exactly the same time! With regards to 2+9 HST sets, the diagram for a 2+9 set this summer involved a stop at Totnes going towards Plymouth on its next working - so can't see 2+9s being an issue providing both power cars are working, simple solution if it isn't would be to just not stop. How heavy is a TS compared to a TGS anyway? |
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The SprinterMeister
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« Reply #153 on: September 12, 2012, 14:00:04 » |
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How heavy is a TS compared to a TGS anyway?
TS is about 1/2 tonne lighter than TGS from memory. |
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broadgage
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« Reply #154 on: September 16, 2012, 18:50:15 » |
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The MTU▸ engines are indeed limited by the power input of the alternator / rectifier / traction motors they are attached to. The 16V4000R41 is in essence a 1800 rpm engine derated to produce the same BMEP at 1500 rpm to give the required power output. Furthermore below 40 mph the traction system is power limited even further in order to keep traction motor currents at a reasonable value, the more current you put through the motors the more heat is created in the motors themselves. You aren't putting anything like 1775 rail HP down until you hit 40 mph, the actual rail hp diminshes with speed below that speed value. It does on all diesel electric locomotives but it is more noticeable with HST▸ due to the higher mechanical axle gearing needed to achieve 125mph running without running the motors at ridiculous rpm figures.
43167-170 were trial fitted with Mirrlees MB190 engines set to 2400 flywheel bhp at 1500 rpm, a major rectifier fire caused the power output to be reduced back to the usual 2250 at 1500 rpm.
There are two other reasons why you may not run the MTU at 1800 rpm, one being the mechanical properites of the alternators themselves and the other being the three phase AC ETS▸ / Auxilary systems which will not accept current at 60 hz / 1800 rpm due to the mechanical /electrical properties of the various motors and devices fed from the supply on both the power cars and the trailers.
The engine speed would indeed have to be limited to about 1,500 RPM in order to produce 50 cycles AC for auxillary purposes. I wonder however if the engine speed could be slightly increased up to 1,560 RPM , that would produce AC at 52 cycles which should be acceptable for 50 cycle equipment, remembering that some grid systems and many generators vary that much. That would provide about 4% more HP, not that much, but it could make the difference between keeping time and not, with an extra coach. |
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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Gordon the Blue Engine
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« Reply #155 on: September 17, 2012, 17:28:47 » |
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SprinterMeister says that the Mirrlees MB190 were de-rated from 2400 to 2250 HP because of a rectifier problem. So that is the issue that needs to be addressed - I think perhaps the idea of increasing crankshaft speed is not the key issue at the moment.
Incidentally, Eurostars and TGV▸ 's have a motor bogie on the car adjacent to the power car, so that the available power can be put down through more axles with more weight for adhesion. As has been discussed before, installed power (ie the diesel engine) is only part of the problem in maximising drawbar pull. AL6 electric locos (high powered, relatively light 4 axle locos with unsophisticated wheelslip protection that used to work on the WCML▸ ) were known to suddenly go into wheelslip at 70mph or more with poor rail conditions.
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« Last Edit: September 17, 2012, 18:45:47 by Gordon the Blue Engine »
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TonyK
Global Moderator
Hero Member
Posts: 6594
The artist formerly known as Four Track, Now!
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« Reply #157 on: September 19, 2012, 23:15:37 » |
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MTU's own press release gives more detail. The pure electric trains are also set to be fitted with one Powerpack each for auxiliary power. Depending on their length, bi-mode vehicles will each have three (five-unit trains), four (eight-unit trains) or five (nine-unit trains) Powerpacks. Prior to today^s announcement, Hitachi has already started intensive tests at their own facilities in Japan using a Powerpack prototype specially prepared by MTU for the joint project. The test program focused on fuel consumption, noise and vibration, power and exhaust emissions. I make that 3.5MW for a nine-car train. |
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Now, please!
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JayMac
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« Reply #158 on: September 19, 2012, 23:45:00 » |
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A good idea to fit one diesel 'Powerpack' to the electric units. As long as it'll generate enough oomph to haul a set when there are the inevitable OHLE failures....
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"A clear conscience laughs at a false accusation."
"Treat everyone the same until you find out they're an idiot."
"Moral indignation is a technique used to endow the idiot with dignity."
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Rhydgaled
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« Reply #159 on: September 19, 2012, 23:55:21 » |
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MTU's own press release gives more detail. The pure electric trains are also set to be fitted with one Powerpack each for auxiliary power. Depending on their length, bi-mode vehicles will each have three (five-unit trains), four (eight-unit trains) or five (nine-unit trains) Powerpacks. Prior to today^s announcement, Hitachi has already started intensive tests at their own facilities in Japan using a Powerpack prototype specially prepared by MTU for the joint project. The test program focused on fuel consumption, noise and vibration, power and exhaust emissions. I make that 3.5MW for a nine-car train. Going purely on the figures posted above and the fact that a 22x has a diesel engine under each coaches Class 221 (or 7-car bi-mode) - 5x diesel engines at 560 kW = 2,800 kW IEP▸ 5-car bi-mode - 3x diesel engines at 700 kW = 2,100 kW IEP 9-car bi-mode - 5x diesel engines at 700 kW = 3,500 kW Class 222 6-car (or 8-car bi-mode) - 6x diesel engines at 560 kW = 3,360 kW Will there really only be 5 diesel engines under a 9-car bi-mode, would that have enough power to reach Aberdeen and Inverness? I haven't read the links, but do they say what the results of the fuel consumption and emissions tests are, how do they stack up against Voyagers and Meridians on the greenhouse-effect scale? A good idea to fit one diesel 'Powerpack' to the electric units. As long as it'll generate enough oomph to haul a set when there are the inevitable OHLE failures.... I disagree. One hopes the OHLE on the GWML▸ will be a reliable design, and they don't increase day-to-day electricity consumption by fitting emergency generators to electric trains in mainline Europe do they? Now on the ECML▸ , where the OHLE seems rather more prone to falling down than one would expect, fitting a diesel powerpack might not be a bad idea but I still think a smaller, much lighter, engine (enough to keep passengers cool/warm but not shift the train) might make more sense as it would add less to the electricity consumption than one capable of moving the train, which would likely be stuck behind a non-diesel-fitted train anyway. |
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----------------------------
Don't DOO▸ it, keep the guard (but it probably wouldn't be a bad idea if the driver unlocked the doors on arrival at calling points).
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TonyK
Global Moderator
Hero Member
Posts: 6594
The artist formerly known as Four Track, Now!
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« Reply #161 on: September 20, 2012, 09:58:12 » |
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Will there really only be 5 diesel engines under a 9-car bi-mode, would that have enough power to reach Aberdeen and Inverness?
One assumes that someone, somewhere has done the maths on this. Speed does not seem to be of the essence after Edinburgh. 2 hours 20 mins to cover 126 miles is hardly supersonic is it? The thought occurs to me that if, after 2019, electrification continues, then the bi-mode trains could have some of their diesel power packs removed, to lighten them and improve efficiency. That seems to be the only difference between bi-mode and "pure" electric - the fuel tank and control systems will be largely similar whether there are 5 engines, or just the one. Looks as though MTU▸ will still get the contract to maintain them for the full 27.5 years though. |
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Now, please!
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The SprinterMeister
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« Reply #162 on: September 20, 2012, 10:41:08 » |
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The thought occurs to me that if, after 2019, electrification continues, then the bi-mode trains could have some of their diesel power packs removed, to lighten them and improve efficiency.
I don't think you can randomly remove 5 - 6 tonnes of engine-alternator set, fuel tank, radiator and control system from under a passenger coach without seriously upsetting the suspension / ride characteristics, Centre of Gravity / Roll axis etc. Some sort of balance weight will be required to compensate if that is the case. I'm still very intrigued as to how you fit a large 90 degree V12 diesel engine-alternator set under a passenger coach without raising the internal saloon floor heights a fair bit. This affects things like stepping height from platform and departure angles of wheelchair ramps etc. I am also intrigued to know how you maintain access to the valve rockers, fuel injectors, 'Top Hamper' etc with the engine in situ under the coach without providing access hatches in the floor. It should be remembered that these hatches are not fitted to modern DMU▸ 's as they were found to be very ineffective in preventing fires from traction equipment on the older type DMMU's from spreading into the interior of the coach. Which is why every DMU from the 14x / 15x onwards have floors with no hatches in them. Insulating the saloon floors from radiated noise and heat could be interesting too. It will be remembered that the Bombardier 22x were also going to use an earlier variant of MTU▸ V12 as the power source but the factors mentioned above caused them to fit the Cummins QSK19-R as it eliminated the problems noted above. |
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broadgage
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« Reply #163 on: September 20, 2012, 11:39:28 » |
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A good idea to fit one diesel 'Powerpack' to the electric units. As long as it'll generate enough oomph to haul a set when there are the inevitable OHLE failures....
Agree, I have misgivings about the whole project, but the fitting of a single diesel engine to a nominaly electric train seems an excellent idea. Not only will the OHLE fail, but the limited diesel power would presumably allow short term/low speed operation on non-electrified diversion routes. Some miles restricted to say 30MPH is probably less overall delay than attaching a diesel locomotive, or transfering passengers to buses. I presume that movements at low speed within depots would also be under diesel power, thereby saving the costs and hazards of electrification in depots. Regular use of the diesel for movement within depots would ensure that the machinery is kept in good working order and does not fall into disuse. |
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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IndustryInsider
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« Reply #164 on: September 20, 2012, 11:45:40 » |
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The International Railway Journal also states "The first train for Great Western will be completed in June 2014, and test operation on the British network is due to begin in May 2015.
Crickey, not long then! |
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To view my GWML▸ Electrification cab video 'before and after' video comparison, as well as other videos of the new layout at Reading and 'before and after' comparisons of the Cotswold Line Redoubling scheme, see: http://www.dailymotion.com/user/IndustryInsider/ |
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