There is a case for a limited extension of the English national bus pass to railways, in cases where local geography makes bus links difficult or very indirect. Bus pass holders' options are limited in certain areas where there is a poor or very indirect bus service for reasons of local geography but a reasonably good rail service. One of these is the Tamar Valley line in Devon/Cornwall and another the Esk Valley in North Yorkshire, both lines surviving because of the difficulty of replacing them with buses. Also there's the Norwich - Lowestoft line where the only crossing of the River Yare at Reedham is by rail or else a chain ferry carrying three cars.
In each case it would be reasonable for a concession to be available for the rail journey. Some work has been done on this in the past and it would be for the relevant local authority to fund the rail concession. In the current financial climate a more general extension of the ENCTS to specific rail lines seems unlikely.
This appears more reasonable.
My understanding of the rationale for bus passes is that it enables the elderly to have access to their local communities, to the shops, to health services and to give them an ability to get out and socialise. The aim is achieved by buses for most. I can see it as being absolutely sensible to offer rail where there is no bus.
However, extending the discount to rail in most cases would actually be a change in purpose. Either the rail route offers a mirror to a bus, but a lot quicker, in which case you are going to see modal shift and potential negatives for those on the bus route when the bus companies reduce service post shift. Or the rail route adds a newer set of destinations and then leads to older people travelling out of the area. Longer distance travel could be highly detrimental to some towns.
My objection is not to including any form of transport, but rather to changing the focus of the policy from supporting local communities to enabling longer-distance travel.