From railrover

Class 98 is the TOPS classification for steam locomotives. This covers both the three BR-owned steam locomotives that work the narrow-gauge Vale of Rheidol between Aberystwyth and Devil's Bridge, BR's last remaining narrow gauge line, and privately-owned standard gauge locomotives that are registered to run on BR tracks.

The Vale of Rheidol locomotives are 98007 Owain Glyndŵr, 98008 Llewelyn, and 98009 Prince of Wales. Normally two out of three locomotives will be allocated to work a day's services.

Hellfire does not track any other Class 98 locomotives, but a steam service does operate two round trips between York & Scarborough on Tuesdays & Wednesdays.