23.11.16. Probably the strangest service number in use in South Yorkshire is the SL1a, a variant of the Supertram Link service which connects Stocksbridge and Deepcar with the tram terminus at Middlewood. Departures from Middlewood are every 10 minutes, matching the tram frequency and alternate journeys operate either way round the Stocksbridge and Deepcar loop as SL1 or SL1a. This run-of-the-mill Dart is heading way from Sheffield along Manchester Road in Stocksbridge, shortly before turning left up the hillside via Hole House Lane.