This view taken at Manchester's Lower Mosley Street bus station dates from the period 1971 to 1973 when Yorkshire Traction worked the service and before the bus station closed.

Yorkshire Traction had always referred to the service as 19 and I don't believe had 'X' on their number blinds. Hence 237 is showing 'YS' as part of the display, which was used to designate the 'Yorkshire Services' joint coach operating pool.

From an original slide in the David Beilby collection, photographer unknown.