https://youtu.be/o7ZhlNiKN8E?si=wMjZGpBpXq2SASYH
A couple of my thoughts:
1) I was always nervous crossing the big bridges, at least in daylight. It was a big relief to get past Clementsport heading east and Weymouth heading west.
2) Though the Dayliner was no TGV, it's clear that it often travelled at a pretty decent clip. I mean, sure, it was a long trip for a mere 216 miles but a certain amount of time could have been saved if there had been fewer stops. My guess is that it wasn't really track geometry that was the problem (particularly curves) but the overall condition of the ROW that slowed it down. Imagine if the line had been upgraded to smooth welded rail with rock ballast, the bridges has been replaced with more modern (and preferably straight) structures that didn't require the train to slow to a crawl, and the level crossings had had gates. Oh, and if the RDCs had been replaced with something more modern and lighter. I know everyone's nostalgic for the RDCs but I would have preferred the service to have been treated as a modern means of transport rather than a kind of holdover from a former age. But we'll never know what could have been.