At the heart of each SFX is a microchip containing the real recorded train sounds and a small motion sensor which detects what the train is doing and replays the most appropriate sounds through the tiny loudspeaker.
Train Tech SFX+ Sound Capsule - Steam Express Locomotive
TTSFX50 Train Tech SFX+ Sound Capsule Diesel Multiple Unit
Train Tech SFX+ Sound Capsule - Steam Express Locomotive HO/OO Gauge TTSFX10
TTSFX11 Train Tech SFX+ Sound Capsule Steam Freight Locomotive
Train Tech SR1 Sound Track Sound Recorder and Player
Train-Tech SFX50+ Sound Capsule Diesel DMU Unit