Running over an hour late on 4 November 2009, 66731 passes Stenson Junction with the 8X23 09:30 Derby Litchurch Lane to Old Dalby special conveying brand new London Underground unit 1001 for testing. The apparent excess of wagons are there to provide the necessary brake force. A number of these trains are scheduled to operate at intervals over the next few years as the new 'S' stock is built at Derby and then delivered to London Underground's Neasden depot by way of the Old Dalby test track.