The post war transformers like what Susann is referring to have large internal circuit breakers and need better protection with modern day circuit breakers installed at or near the transformer output terminals. 7 to 8 amps is usually enough for most trains.
Another thing to consider if using older transformers is the use of a TVS or transient voltage surge protector, which can be purchased online from a place like mouserelectronics.com Make sure it is bi-directional and around 36 volts AC.
Scott's Odds and Ends used to sell a circuit breaker set-up with TVS units for over $45.00. They have 10 amp breakers and TVS units installed but you wire it to the terminals.
Personally you can buy the breakers & TVS units much cheaper from an online source and make your own breaker & TVS box then buying from Scott's.
Lee Fritz
