The big problem with HSTs is having a very powerful locomotive on each end instead of a power car full of passengers. Wasteful on fuel also with a short set, even with one engine shut down still dragging extra unnecessary weight.
With double tracking not being feasible throughout, more loops with trailing sidings each way are the answer. This allows not only passing but overtaking at the same time, perhaps both ways. Such a system works very well in Malaysia on their 327 mile long single track branch line as well as on their main lines in the past, most now being double track, where the old three trains a day each way, plus freight, has now become about 4 times that and all fully booked in advance sometimes with more trains being ordered to increase capacity. 4 trains passing/crossing/overtaking at one station on a single track either side was quite a common occurrence at many stations, some of which only had a single platform! The loops were often large enough to hold two full length trains.
Travelling on the local passenger service is/was a great way to see the scenery and all the other trains, especially on the older trains, some of which had no doors or windows!
) though as I'd think they would be served by the more frequent services. Just a case of speeding up where you can like going non-stop from Perth to Haymarket. It's the same as the Highland Chieftain calling at the likes of Northallerton and Grantham etc, would be an absolute nightmare!
