Railperf
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- 30 Oct 2017
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Taking the fastest runs by comparison, nothing beats a voyager on all engines, but the low speed sections through Devon don't really allow Voyagers to extend their legs fully. Best comparison would be the 100mph climb to Wellington from Taunton or Tiverton Parkway.
As said before the IET's good low speed acceleration is probably similar if slightly slower than Voyager to 40mph, then the Voyagers are pulling away. The Devon banks limited to 55/60mph - so no real advantage there. What the IET's gain at low speed over an HST is lost on a decent climb. But the more precise and accurate braking again seems to gain IET's time over an HST so that most of the sub 100mph sections the IET's are as quick as HST's formerly were.
From my own analysis, GWR IET's on diesel match former HST schedules easily on sub 100mph track. Increase speed limits to 125mph and IET's are slower than HST. But a Voyager beats both on 125mph track where its power to weight ratio is superior in getting it up to speed easily.
As said before the IET's good low speed acceleration is probably similar if slightly slower than Voyager to 40mph, then the Voyagers are pulling away. The Devon banks limited to 55/60mph - so no real advantage there. What the IET's gain at low speed over an HST is lost on a decent climb. But the more precise and accurate braking again seems to gain IET's time over an HST so that most of the sub 100mph sections the IET's are as quick as HST's formerly were.
From my own analysis, GWR IET's on diesel match former HST schedules easily on sub 100mph track. Increase speed limits to 125mph and IET's are slower than HST. But a Voyager beats both on 125mph track where its power to weight ratio is superior in getting it up to speed easily.
in damp conditions or also dry? Is that because the brakes are much sharper to apply compared to HST where the brakes progressively come on along the train?Absolutely. IeT beats Hst hands down in terms of pulling away in slippery conditions. Worlds apart...however braking wise, I've noticed IETs slip a little more than HSTs did, although not enough to warrant concern.