To celebrate its 50th anniversary, the railway has hired headlining steam engine Royal Scot, but she has a problem with her boiler, carriages that haven't been serviced in five years, and no-one even knows if she will fit the line.

The marketing manager targets teachers in hope they'll return with students, Chris reveals how some bridges are in desperate need of repair, and Piglet has a race against time to fix an engine which is hoped be on display for the Tour de Yorkshire.

General manager Chris calls a crisis meeting, believing the only chance the railway has of making it through the busy summer season is if an overhaul of Repton - a 1934 Schools-class engine - is completed. This engine has been undergoing restoration for the past five years, but now it is going to be all-hands-on-deck to try and get it back on the rails quickly.

A summer heatwave brings record numbers to the railway, but also risks fires in the dry national parks through which the line runs, putting the very existence of the railway in danger.

Head boilersmith Mark and his fiancée Emma choose their beloved B1 steam train to lead their wedding, but not everything goes to plan.

For the annual Gala Festival, the NYMR plans to swap their precious Q6 engine with another from the Severn Valley, but there is a crack in the engine box and no-one to fix it on short notice.