These posters served as warnings about potential hazards on the railway during the years 1965-1968. They were displayed at various stations to inform passengers and the public. The full collection of posters can be seen at the Railway Museum in Bangkok. The warnings include reminders not to ride on the roof of trains, not to stand on the steps to avoid hitting bridges, and not to stand too close to the platform edge to avoid being hit by a train. Other warnings caution against crossing tracks without looking out for trains, not to disrupt communication equipment, and not to bring animals onto the tracks.
https://www.thaitrainguide.com/2022/06/10/railway-safety-posters/