The sensor was small enough for an N-gauge train, which translates to 1:148 scale or about 9mm from rail to rail. His idea was to build a tiny control board that could fit inside the locomotive ...

Price: Direct-current model with 21-pin plug, $239.95; with dual-mode sound decoder, $289.95 Era: Mid-1990s to present (varies based on paint scheme) Manufacturer: Rapido Trains, 382 High St., Buffalo ...