northernbelle
Member
- Joined
- 10 Oct 2018
- Messages
- 689
Power to weight ratio is irrelevant on a stop/start working like these. HSTs only have the edge on the sprints between Exeter and Highbridge - IETs are quicker on the shorter hops more or less everywhere else along the route.There is no reason why an HST should lose time. In fact, it should be able to beat the IET on diesel as a 2+4 HST has a rather better power:weight ratio (15.8hp/t against 11.6hp/t for the Hitachi dross).
The ability to lay full power down from the outset and not having vague braking gives IETs a performance edge on these workings.
They do above a certain speed. But on services with 30+ station calls the initial getaway becomes more relevant.A better power to weight ratio doesn't necessarily mean better acceleration as it relies on how much of that power you put down to the rails. However, it wouldn't surprise me if they accelerated faster than the IETs.
Can be a nightmare. The dwell itself seems to be worse on an HST too - people seem to be slower boarding/alighting them.2+4s also loose time because apart from a couple of stations dispatch must be done from the TGS so if you have had to use SDO you have to move back to the TGS. If you have a ramp at Highbridge and the unit is in reverse formation you have to move the train etc it's a right old faff. Once you loose time you never get it back on a 2+4.