They might be only one carriage. One carriage four times an hour gives a far more usable service than four carriages once an hour.
True, until you realise that there are,
AFAIK▸ , no single carriage units left in
GWR▸ 's fleet: I can't recall the last time I saw a Class 153 unit anywhere.
Dave
Take a look at Cardiff / Portsmouth. When 5 of 6 car loco hauled trains running every few hours that were less than crowded were replaced by 2 car trains every hour - about the same number of carriages running overall - passenger numbers rocketed. Frequency does it!
But ... indeed, no single carriage units left on GWR (nor in East Anglia). Transport for Wales has quite a few - some having loos converted to disabled (and that does leave a handful of seats) and others always being used to strengthen trains. Some also with a temporary allowance to run this year without disabled loo. Northern still has some, East Midlands a few, and Scotrail are converting some for carriage of cycles and other paraphernalia. And a number are stored.
Single carriage trains were know in the past as "Coffin Nails" as they were the last day to day trains to use a line as wound down prior to closure. But more recently they have worked very well for us (and for other lines such as Paignton) providing experimental services at less than the cost of a multi-carriage train as passenger numbers were built up - so they have become to some of us a passing phase on the way up, rather than a passing phase on the way down. I do suspect that a line that's running with most of its trains single carriage over an extended period is rarely going to make economic sense. So 4 trains an hour on "The Beach" even if not all the way to Severn Beach, please. They probably cannot be 4 cars any longer though - my understanding is that some of the platform upgrades reduced the maximum length of a train than can open all doors to just three carriages,
