People really need to let go of their nostalgia for the HSTs. We all love them but it’s simply a fact that they’re outdated and only going to deteriorate further. I’m not even sure why HSTs are being suggested in this thread. They’re so unsuitable for the WoE services. As has been mentioned previously, 159s are perfect. What’s needed is a modern MU of similar specification and ideally bi or tri mode.
While I admit that it’s the wrong thread for the current discussion, but were not suggesting them for the WoE, but rather a similar new build design as a replacement for XC’s 22x fleet.
The WoE needs a train (ignore the loco vs HST vs MU thing for a minute) that is capable of operating on 750V DC Third Rail and diesel. It needs to have plenty of power to keep to time over Honiton Bank especially, but also the other banks on the route. OHLE capability is currently not needed, but a pantograph well should be built in even if a pantograph is not installed from the get go to allow an addition of one should the Exeter St David’s or Salisbury are ever be wired up.
I am unaware of what the speeds are west of Salisbury, but I believe that 100mph (correct me if I am wrong) is the limit west of Salisbury and therefore would be adequate for the route.
Diesel power needs to be fairly high as these train will be heavy, especially if they’re both third rail and OHLE capable along side the diesel engines. Adding a small battery to allow low emission departures from non electrified stations is an option, but again, this adds weight and would need go be considered when deciding on installed diesel power.
Back to MU vs LHCS/HST type setups. Personally, while the reliability has been sub optimal, I think that the format of the Stadler 755’s is a game changer. The have the advantages of MU and LHCS.
- They can be split and joined as the TOC pleases
- They have redundancy thanks to multiple engines
- They have distributed traction
- They can be reversed easily
- They don’t have engines under the floor so are comfortable and quiet.
- They have the performance of MU’s due to their high power
- TA charges are low
- Fuel consumption should be lower, depending on how you’re measuring it
The only disadvantage that Stadler 755’s have over normal MU’s is the power car that wastes space, however it is only 7m which isn’t all that much on an 80m train. I have previously suggested a 2 x 6 formation out of Waterloo, but in reality, a mixture of 6 and 4 car sets would be better.