Thomas
RA doesn't play across the train lines - well not intentionally. There are two 'back tees' introduced for the 1998 Australian Open which do have tee shots playing just over the lines, but they are not in regular play, except for the best of players.
The issue of play over the railway lines is (apparently)one of the reasons that encouraged RA to engage Mackenzie in the 1920's when he visited Australia (in particular, Royal Melbourne). The original routing (Cargie Rymill) did have holes that played across the then steam trains. The State Government advised that it intended to electrify the railways, so the club needed to look at re-routing to avoid the gantries that would be built. Mackenzie came, some of his plan was installed (including eliminating the rail crossings on lines of play) and the government decided a decade later that they wouldn't electrify the lines after all - they converted from steam to diesel.
80 years on, the diesel trains are still running, although a different line has just been electrified. Other lines which were to be electrified have not, and there are no plans to electrify the small line through the RA course.
As an aside, I quite like the second hole tee shot across the railway line, which makes the tee shot on an otherwise straight hole as one having a Cape characteristic. The fourteenth hole tee shot doesn't really have anything to be said of it from across the line.
James B