I think in a rural area it would look a lot like this.
take out the solar battery and lights for the 1930s effect.
The gates would either be timber or galvanised. The person crossing would manually open the gates on both sides and close them after he crossed. Keep looking both ways LOL.
In urban areas they were probably manned. By the 30s big cities and towns had electricity, but I doubt it would be automatic anywhere back then, or warning lights either. But I don’t know.
Contact a railway historical society in Ireland for more details.
A lot of people worked on that project, my uncle was one of them.