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Old 19th May 2014, 06:36   #1
SpacePhoenix
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Default Class 800

Was reading about the class 800s, on wikipedia it says that the diesel engines are under the floor. With the emissions/pollution regulations as they are, isn't any new design of DMU or DEMU that utilizes under-floor engines dead in the water before it even makes it to the drawing board?
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Old 19th May 2014, 06:56   #2
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Only if you take "internet received wisdom" as "fact".
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Old 19th May 2014, 07:43   #3
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I think I know where it has come from. There was a rush to re-engine the last of the HST power cars as MTU's new version of the 4000V wouldn't fit in the Power cars. It's easier to accommodate the extra catalytic converters and other emission reduction gubbins in a new design then to shoehorn it into an existing one.
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Old 19th May 2014, 15:09   #4
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Was reading about the class 800s, on wikipedia it says that the diesel engines are under the floor. With the emissions/pollution regulations as they are, isn't any new design of DMU or DEMU that utilizes under-floor engines dead in the water before it even makes it to the drawing board?
IIRC the issue was mainly about the economics involved especially for the number likely to be needed and where, and the IEP does not appear to be a cheap train by any stretch of the imagination - that said 26m carriages presumably provides more room underneath than a 23m Turbostar carriage for example, while the door layout allows a higher floor.

Chris

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Old 19th May 2014, 17:56   #5
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I think the rumour is down to the newer compliant engines firstly not being available at the time (they are now) and secondly having to be larger and not fitting underneath an existing design like a Turbostar.
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Old 19th May 2014, 18:11   #6
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There is a new version of the QSK-19 (used underfloor on Voyagers, Adelantes, Meridians and Pennines) that is compatible with the latest restrictions. It's the QSK-19R. Whether it would fit on existing designs is one thing, but it could easily be fitted to a new design built around it.
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Old 20th May 2014, 01:29   #7
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Quote:
Originally Posted by Chris125 View Post
IIRC the issue was mainly about the economics involved especially for the number likely to be needed and where, and the IEP does not appear to be a cheap train by any stretch of the imagination - that said 26m carriages presumably provides more room underneath than a 23m Turbostar carriage for example, while the door layout allows a higher floor.

Chris
Sounds lovely already, higher floors, thumping great big 700kW MTU 12V 1600 R80L constantly thumping away underneath almost constantly... reminds me of something else with higher floors, and thumping great Cummins engines constantly droning away underneath all the time.

It will be interesting to see how Hitachi accommodate the rather large MTU powerpack though, but I hope they do a good job of soundproofing first, and better underfloor mechanical layout than Alstom did of the Adelantes!
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Old 20th May 2014, 04:17   #8
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Sounds lovely already, higher floors, thumping great big 700kW MTU 12V 1600 R80L constantly thumping away underneath almost constantly... reminds me of something else with higher floors, and thumping great Cummins engines constantly droning away underneath all the time.

It will be interesting to see how Hitachi accommodate the rather large MTU powerpack though, but I hope they do a good job of soundproofing first, and better underfloor mechanical layout than Alstom did of the Adelantes!
I would expect the engine to be driving a generator/alternator which feeds traction motors for final drive, after all the IEP/Class 800 comes in either electric only or electro-diesel ("bi-mode") ^flavours^, and running like a DEMU when not drawing overhead traction power, rather than a mechanical/hydraulic unit like the Adelantes. With energy transferred as electrical current, as long as the wires are properly insulated and everything else is up to specification then it's pretty hard to go wrong.
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Old 20th May 2014, 10:01   #9
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Quote:
Originally Posted by fgwrich View Post
Sounds lovely already, higher floors, thumping great big 700kW MTU 12V 1600 R80L constantly thumping away underneath almost constantly... reminds me of something else with higher floors, and thumping great Cummins engines constantly droning away underneath all the time.

It will be interesting to see how Hitachi accommodate the rather large MTU powerpack though, but I hope they do a good job of soundproofing first, and better underfloor mechanical layout than Alstom did of the Adelantes!
I suggest you read the IEP specification if you haveb't. As with most new tenders, they have decibel limits for various situations and the volume in the passenger saloon shouldn't exceed the volume of a normal conversation.
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Old 20th May 2014, 11:06   #10
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I really don't see the issue with under-floor engines, at least in new stock. I've never found the Voyagers, for example, to be too loud. I actually prefer them to the creaking and squeaking of the vestibules in Mark 3 coaches. They just suffer from being too short for the job they're given.

Anyway, I hope the IEP is a good train because we're going to be stuck with it for a while!
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Old 20th May 2014, 11:34   #11
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I really don't see the issue with under-floor engines, at least in new stock. I've never found the Voyagers, for example, to be too loud. I actually prefer them to the creaking and squeaking of the vestibules in Mark 3 coaches. They just suffer from being too short for the job they're given.
When you've been sitting on similar trains (one or two Meridians, in my case) for long-distance journeys, and the engines have been faulty and vibrating horribly the whole time, then you come to realise that it's not always a good plan to keep them underfloor!
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Old 20th May 2014, 13:15   #12
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Please remember that the vast majority of passenger kilometres on the IEP fleet will be done under the wires where there would be no need for the diesel engine to be active. On the East Coast the worst case scenario is the Highland Chieftan but that will still spend most of its journey under the wires - currently there are 4 hours and 39 minutes (London-Haymarket) under the wires compared to the total 8 hours 6 minute journey time. With EGIP wiring up to Dunblane, this becomes 5 hours 28 under the wires around the same time that the IEP fleet will replace the HSTs on EC. As the rolling programme of electrification continues this under-wire journey time increases more and more and so there will be less and less time spent with the diesel engine running.
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Old 20th May 2014, 13:18   #13
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Worse engine Cummings have ever made. Noisy, unbalanced vibration and leak oil and water like theres no tommorow.
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Old 20th May 2014, 14:59   #14
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Quote:
Originally Posted by asylumxl View Post
I suggest you read the IEP specification if you haveb't. As with most new tenders, they have decibel limits for various situations and the volume in the passenger saloon shouldn't exceed the volume of a normal conversation.
Thats still pretty loud.. Although I guess that might include the volume under heavy acceleration too?
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Old 20th May 2014, 16:17   #15
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Quote:
Originally Posted by cf111 View Post
I really don't see the issue with under-floor engines, at least in new stock. I've never found the Voyagers, for example, to be too loud. I actually prefer them to the creaking and squeaking of the vestibules in Mark 3 coaches. They just suffer from being too short for the job they're given.

Anyway, I hope the IEP is a good train because we're going to be stuck with it for a while!
I'd rather have that creak and squeak of those wonderfully comfortable Mk3s than the awful vibration I feel through the floor in a Voyager.

The jury's out on IEP. Many feel it's going to be an expensive piece of crap. It's certainly going to be expensive, and it will have an incredibly hard act to follow. Both the HST and 91/Mk4s were and are excellent trains that have proven to be very good at the job they do.

But then, many felt the same about HST when it took over from the Deltic. All we can do is wait and see.
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