First appearance of Malcolm Atterbury in the role of train passenger John Bixby. Atterbury appeared in six episodes as Bixby, all during the first season when a few supporting characters were shown repeatedly in multiple episodes in an attempt to provide some amount of familiarity with members of the train. This practice did not last beyond the first season and these characters did not appear in subsequent seasons with the exception of Terry Wilson (Bill Hawks), who was the only supporting character to join the series as a fully credited member of the regular cast.
The "horse pistol" referred to would be a Colt's Third Model Dragoon pistol, which was so nicknamed because it was so heavy only mounted riders could carry them easily. They were known as the weapon of choice for the Texas Rangers.