My advice for today and indeed ongoing into early next year to Melksham passenger who want to use the train is ..
1. If you are working in Swindon or Chippenham during the week, there's a train at 08:02, and a return service at 17:35 17:50.
2. For anything else, catch the bus.
* For Bath, Bristol and the west, services 271/272/273 which stop in Manvers Street opposite the station for onward trains to Bristol and South Wales, and connection.
* For Trowbridge and Chippenham, use service x34 which serves Trinity Church in Trowbridge (except of Sundays when it terminates in the town) and the BUS station in Chippenham (early inbound and mid / late afternoon outbound journeys serve the railway station too)
Rail replacement buses - Chippenham, Melksham and Trowbridge STATIONS are also running, including on New Year's Day when the regular x34 / 271/2/3 are not running. They also provide an evening service which the x34 does not.
Headed via Frome? Catch the x34 which runs direct from Trowbridge to Frome and is much quicker that the rail replacement which take you via Westbury.
Headed for Westbury? Catch the rail replacement, but remember that if you are going beyond Westbury it will be buses beyond there too.
Train and bus departures vary on a few days - but for the most, take a look at
https://www.mtug.org.uk/winterttm.pdf which lists the train and rail replacement services on typical days
