After stopping for a member of the crew to open and close the Horsenden Lane level crossing gates, 50008 Thunderer & 50015 Valiant get underway again on 7 April 2025 with the 15:15 Princes Risborough to Chinnor service, during the Chinnor & Princes Risborough Railway's 'Class 50 Mileage Day'. This was running over an hour late.