1K71 is the weekdays 05:10 Bristol Temple Meads to London Paddington service. It is now the only direct train between Bradford on Avon/Trowbridge and London. It is also unusual in another way as the train is not scheduled to stop at Bath Spa.
I should have added that Cross Country run a service on a Saturday that runs through Bath but doesn't call there. 1C11 (the 06:07 Bristol Temple Meads to Plymouth service) is routed via Bath and Westbury for route knowledge retention purposes. An empty coaching stock working runs the other way on a Saturday evening for the same reason running as 5C59 (the 19:18 Paignton to Bristol Barton Hill depot working).