The Hertford Loop Line is a branch of the East Coast Main Line, part of the Northern City Line commuter route to London from Hertford and other Hertfordshire towns and an occasional diversion route for the main line. The line is part of the Network Rail Strategic Route 8, SRS 08.03 and is classified as a London and South East Commuter Line. This would be a fun route to play because the gradients/curves make for a challenging drive that keeps you focused! Electrification: 25 kV AC OHLE Rolling Stock: Great Northern Class 717 EMU Line length: 24 mi (39 km)
Would probably be better off coming as part of a KGX - Peterborough route (the current ECML doesn't go to London btw).