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An IET driver comments.

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An IET driver comments. - Posted: December 17, 2017 - 2:00 PM Quote and reply
Don't know if this adds anything but just in case:

AFAIK all the (IET) engines are the same, the power output is software controlled and can even be altered on the move (though not by the driver!).
GW driver Google Groups.

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IEP Performance - Posted: December 18, 2017 - 10:38 AM Quote and reply
Reproduced from Roger Ford's (Modern Railways) monthly blog re performance of class 800's

Class 800 performance logs

Steve Jobs of Apple was credited with the ability to create a ‘reality distortion field’ when his team were developing the original Macintosh. A similar field surrounded the Department for Transport when the Intercity Express Programme specification was being developed.

One of the longest campaigns in Informed Sources history has seen me patiently explaining why DfT’s belief that distributed traction compensates for a shortage of installed power is delusional. But people have continued to cling to it like a security blanket.

However, the train is now in the metal, in the form of the Class 800 and, entering service with Great Western. And, as they say in motor racing ‘when the flag drops the b*llsh*t stops.
So I was delighted to receive the first analysis and modelling of Class 800 logs to date from the Railway Performance Society (RPS) And very interesting it has proved too.

For example when the delays to GWEP meant that the Class 800 bi-modes were going to be running under diesel power for over a year, DfT finally conceded that the 750hp (560kW) ‘reliability rating’ of the Class 800 MTU engines was not enough to match IC125 times.

So as part of the deal which saw the 9-car electrics for GWR delivered as bi-modes, Hitachi agreed to ‘unmuzzle’ the engines and run them at their 940hp (700kW) commercial rating. This added £300 million to the cost of the IEP contract.

Thus far the RPS members have failed to find any evidence of the uprating, analysis being consistent with the 750hp power output. Nor does analysis of performance with an engine out indicate that the automatic uprating of the other engines in the set to the commercial rating is happening.

These are, of course, early days for the Class 800 fleet, with the first sets being bedded in. I would not be surprised if the engine management software was locked at the Reliability rating. In addition, according to Informed Sources, GWR is under pressure from DfT not to ‘unmuzzle’ the engines.

As part of the £300 million deal the engine reliability regime within the contract is suspended for uprated power units. If an engine fails, Hitachi is held harmless for any performance regime penalties during the rest of the diagram and DfT compensates GWR.

One interesting feature to emerge from the analysis is the comparative performance from a standing start. Obviously the Class 800 zips away, but then the IC125 overhauls it. Way back in the IEP saga, my brother, the engineering professor, analysed just such a ‘drag race’ as part of my efforts to discredit the distributed traction fallacy. Using just published acceleration curves and excel he was within 20% of 2017 real world performance. Clever stuff, eh?

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