A visit to an heritage railway does not mean always that you can have a ride on a train pulled by a steam locomotive. When I visited the Mid-Norfolk line travel was courtesy of a diesel multiple unit of 1960s vintage.
In my part of the world we are well served by heritage railways: Kent & East Sussex, Bluebell, Spa Valley and Romney Hythe and Dymchurch, the latter being narrow gauge. This year the Spa Valley Railway opened the line between Groombridge and Eridge and it is possible new to travel by a Southern train on the Oxted-Uckfield line, change at Eridge and thence by the Spa Valley to Tunbridge Wells.
Soon, the Bluebell will have cleared the mountain of rubbish in a cutting and made a connection with the Southern at East Grinstead. See: http://www.bluebell-railway.co.uk/bluebell/ext/extprog.html
The Rother Valley Railway is slowly re-building bridges on the line from Robertsbridge and plans to make an end-on connection just west of Bodiam with the Kent & East Sussex Railway.
A holiday would not be complete without a ride on a heritage railway. So far I have travelled the East Somerset, West Somerset, Ffestiniog (the orginal railway had only one 'f'), Paignton and Dartmouth, Watercress, South Devon, Talyllyn, Barnstaple & Lynton, North Norfolk, Swanage, North Yorkshire Moors and Brecon Mountain railways.
Still plenty to go. In particular I am looking forward to visiting the Severn Valley, Midland Railway Centre, Great Central, Gloucestershire-Warwickshire and Llangollen railways. The East Lancashire is on my list, but it might prove a tad difficult to persuade my wife to spend a holiday in Bury.
2012 will see us visiting Wales and I have plans to visit the West Highland Railway.