I'm working my way through the Class 31 journey mode, after completing "Tank Trouble" and selecting continue journey the game puts me into the Class 37 journey mode.
Same for me. I've to go back to the Journey menu again to get the next one. I've only one Journey left now
Nice to know the class 31 actually has a journey mode. A lot of the older loco DLCs don't ie. Class 40 and 08 for NTP (freight pack) or the GP40-2 for CSX Heavy Haul, even though the locos that came with those routes do.
