Not really sure there's much of comparison to be made. Just look at a map and see what roads have to be used to get between the stations along the line. From Oxford to Moreton-in-Marsh, the routes the coaches are forced to use mean it takes getting on for twice as long as driving along the A44, especially if the coach has to serve Shipton.
Regret to say that "coaches" here means "coach".
If we were talking about "coaches" then there'd be one to the difficult-to-serve places like Shipton and another which ran directly to Moreton and beyond.
3:14 for a journey from Oxford to Worcester can only be described as excruciating. The time involved is designed to ensure that there are no passengers.