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Post by d7666 on Jul 3, 2013 10:12:04 GMT
None of the announcement about 378s 5th car state if it is a Motor or a Trailer.
378s are MMTM. 376s, the next nearest type, are MMTMM, and all Electrostars are formed of all M except one T.
Since 378s already have their one T, does anyone know what the 5th 378 car is to be ?
I assume it will be another M but anyone know for sure what has actually been ordered ?
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Nick
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Post by Deleted on Jul 3, 2013 11:17:18 GMT
They are MOS's. They would struggle in certain conditions with the gradients on the ELL otherwise. We can drive with one of the 5 motors out now but we have to be very aware of section gaps.
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Post by d7666 on Jul 3, 2013 21:13:09 GMT
They are MOS's. They would struggle in certain conditions with the gradients on the ELL otherwise. We can drive with one of the 5 motors out now but we have to be very aware of section gaps. Thats true about gradients had not thought of that, its obvious now you say it  Not sure what you mean by " one of the 5 motors out" as a 4car 378 has three motor coaches total 6 traction motors ? And, less certain, I thought the traction motors are paired by traction pack, so cut out 2 or 4 when defective ? -- Nick |
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Post by redbond on Jul 3, 2013 21:46:08 GMT
A 4 car 378 has 9 traction motors, with a semi-powered and fully powered bogie on each DMOS/MOS. I'm not sure the extra MOS would require 3 motors but no doubt it will due to keeping it exactly the same as the others.
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Post by d7666 on Jul 3, 2013 21:54:46 GMT
A 4 car 378 has 9 traction motors, with a semi-powered and fully powered bogie on each DMOS/MOS. I'm not sure the extra MOS would require 3 motors but no doubt it will due to keeping it exactly the same as the others. Are you sure about this ? I thought the motor cars are all Bo-2 i.e.one powered and one non powered bogie. 376s are certainly all Bo-2. Every reputable source I know of describes 378s as "2 x 250 kW motor" per motor coach. That does not mean this is right of course, they could all get it wrong. But 3 traction motors would be really odd. And, if you are right, my question stands, since "1 out of 5" is as illogical for 9 motors per unit as it is for 6 motors per unit. -- Nick |
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Post by Deleted on Jul 4, 2013 8:00:57 GMT
Sorry, I should have said "one of the powered bogies out". Redbond is correct to say that there is a fully powered and semi-powered bogie on the the DMOS's. d7666, the 378's do differ from the 376's for the very reason of the power requirements for the gradients. You are right that it is very hard to find categorically reliable information on the web though.
I had believed there to only be one powered bogie on the MOS Redbond? Is this incorrect? I believed there to be 5 powered bogies in a 4 car formation (DMTD - or on the NLL DMPD). The traction status screen shows power to two bogies on the DMOS-A and DMOS-B but only one on the MOS, no?
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Post by d7666 on Jul 4, 2013 14:02:31 GMT
Hmmm this is more complexicated than I previously understood.
I always knew 378s diverged from 376s but never realised as far as this.
So let me try and get this right then, comparing Electrostar with Capitalstar :
a 4car 377/375 is 2Bo-2Bo-22-Bo2 - I know that iss right
a 378 is - this is my question - 1ABo-2Bo-22-BoA1 ?
Have I got the traction motor layout right i.e. the DMOS has one bogie with one motor, that its the outer bogie, and its the inner motor on that bogie ?
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Nick
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Post by d7666 on Jul 4, 2013 14:15:32 GMT
Hmmm this is more complexicated than I previously understood. I always knew 378s diverged from 376s but never realised as far as this - I thought below the underframe they were the same ! So let me try and get this right then, comparing Electrostar with Capitalstar : a 4car 377/375 is 2Bo-2Bo-22-Bo2 - I know that is right a 378 is - this is my question - 1ABo-2Bo-22-BoA1 ? Have I got the traction motor layout right i.e. the DMOS has one bogie with one motor, that its the outer bogie, and its the inner motor on that bogie ? -- Nick |
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Post by Deleted on Jul 4, 2013 15:16:56 GMT
You are certainly correct with regard to the DMOS and the layout (in all respects) of that. I may have confused myself over the MOS. Redbond might be right about that also having 3 motors with the same configuration as the DMOS. I will have to look under one again when I get a chance. I'm still thinking back to the traction screen though.
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Post by d7666 on Jul 4, 2013 16:50:02 GMT
You are certainly correct with regard to the DMOS and the layout (in all respects) of that. I may have confused myself over the MOS. Redbond might be right about that also having 3 motors with the same configuration as the DMOS. I will have to look under one again when I get a chance. I'm still thinking back to the traction screen though. Thanks! Any update welcomed. I've been travelling on the things ever since they started on the North London -> Clapham Junction services and I never noticed this motor layout, although I wasn't looking out for a difference in this respect. Something I had noticed though on 378s compared to other 37x : on a 4car 378 the pantograph end of the trailer is not in the middle of the train. On 4car 357/375/377 the pan is, as far as practical, in the middle of the unit, ny being adjacent ot eh other intermediate car. On a 378 the pan is nearest the outer car. I wondered why this is and no-one came up with a sensible suggestion. I assume the 5th car will be inserted at this end, making it less of a point which way round the trailer is. -- Nick |
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Post by Deleted on Jul 4, 2013 20:58:16 GMT
AIUI, the extra car matches the existing plain motor car, and goes in the same 'half unit' (which has already gone from DM to DM+M) - the other 'half unit' remains as PT+DM (with the pantograph next to the DM).
Three cars is apparently the maximum for a half unit, which might cause a problem if they decide on a further increase to six!
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Post by Deleted on Jul 6, 2013 11:09:55 GMT
I suspect the extra coach will be an M with three motors as with all the other powered vehicles.
To my knowledge the motors used in the 376/378/379 are slightly different than those used in the 375/377 and are rated at 200kW rather than 250kW.
Some observations. A 378 accelerates at about the same rate as a 4 car 375/377 on DC. A 378s normal starting tractive effort is 150 kN whether on AC or DC. The difference is on DC this figure quickly falls off above 25 mph whereas on AC the full 150 kN doesn't drop off until 35 mph giving fantastic acceleration.
A 375/377 produces 132 kN starting tractive effort. 44 kN per powered vehicle or 22 kN per motor. The 378 based on 9 motors gives just over 17 kN per motor. When fully loaded a 378 can produce 180 kN starting tractive effort but even that is 20 kN per motor - less than a 375/377 (22 kN per motor) leading me to believe that the 376/8/9 are rated at 200 kW and the 375/377 are 250 kW.
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