The Londonderry Sentinel of 9th March 1966, carried a very interesting article on a Mrs Ruth Walker of Goshaden, wife of a Samuel Walker. This Samuel was apparently a former UTA employee, so presumably the Ulster Transport Authority (which ran rail and bus transport in Northern Ireland and operated from 1948 until 1967). A possibility for the Samuel you are interested in, perhaps.
Other articles on this Ruth Walker indicate she was originally from Wales, whilst some say England. These also refer to her husband as a 'transport worker' and that he/they 'took over a derelict farm in Goshaden.' By 1960, she had apparently been in Northern Ireland for 13 years.
Perhaps worth reaching out to the Northern Ireland Goat Club to ask if any current members have links to and/or knowledge of, anyone related to this Ruth and Samuel and would be willing to pass on your details to them, in hope they might then contact you and confirm or rule out Samuel as having been one and the same as the railway driver.