For those interested in holiday trains in ye olden times in Cornwall, this thread may be of interest - post#26 especially...
https://www.railforums.co.uk/threads/summer-saturday-services-1950s.135629/
Thanks that confirms what I thought that there was at one time a through service from Paddington to St Ives.
I don't think it would be possible now, because the station platforms were greatly reduced to make room for a bigger car park. Though I suppose at least the line survived I believe it was scheduled to close in the Beeching report but given a last minute reprise.
This branch seems unusual too in that there are two bay platforms for it at St Erth I believe, though I've never seen them both in use. I did wonder if that was a left over from holiday trains.
Whilst the freuent trains on the Truro - Falmouth line does mean it's not possible to run through trains any more I do find it very encouraging to see how that line has boomed. I do remember in the late 1990s, it was a less than hourly service, often poorly connecting with the mainline and with the trains usually extremely quiet. Now it has train every 30 minutes, which always seem to be busy. It does show that if you give a line a frequent and reliable service they will use it. I do wonder if similar could happen with Newquay, if any of the TOCs could be bothered to give it a go, by running more frequent trains, and at times useful for commuters too.
The Looe line was another where the timetable used to be useluss for anyone wanting to commute (E.g. to Plymouth), but it is also much improved now with trains running at times to make a commute to Plymouth viable.