Which cases are there of on-demand buses being reasonably useful ways to visit heritage railways?
- I've used Callconnect (Lincolnshire) from Wansford to Peterborough, having got to the Nene Valley too late for the last eastbound train that day, and their area also covers Rocks by Rail and the Lincolnshire Wolds Railway
- FoxConnect can be used between the Battlefield Line and Atherstone
- Flexibus covers most of East Sussex, with journeys up to 9 miles on routes not otherwise served by public transport. As long as there's a gap between Robertsbridge and Bodiam, it helps for the Kent and East Sussex Railway; less so for the Lavender Line (hourly buses to Uckfield and Lewes) and potentially the Bluebell Railway (I don't know if needing to change counts as served by a fixed route, if insisting on going to / from Sheffield Park by public transport rather than East Grinstead). The Bluebell Railway and Lavender Line are close enough to each other to use Flexibus between them; the Spa Valley Railway's slightly too far from those two, and the K&ESR's too far from any of those three for one Flexibus journey.