The heyday of steam age will be celebrated by the Gwili Railway, Bronwydd Arms Station, Bronwydd, Carmarthen, tomorrow (Saturday) and Saturday.
The clock will be turned back twice in one weekend to commemorate the Great Western Railway, or God's Wonderful Railway, as it was nicknamed.
Taking star billing will be one of the company's former Prairie tank engines, built in 1924, and visiting Carmarthenshire from the Severn Valley Railway in Shropshire.
Also on display will be a historic Great Western Railway coach which was built in 1888 and was used for many years as a dwelling in Pentrecwrt near Llandysul. It was rescued in 1991 and is now nearing the end of a volunteer-led 17 year restoration.
There will be the opportunity to turn up and drive a steam engine for £10, as well as rides on a vintage miner's train hauled by an ex-National Coal Board engine.
A 71/4 miniature railway will be operating as well and a Routemaster bus will be on hand to give rides.
The event starts at 10 am on both days, with car parking available at Bronwydd Arms.