The TSU-4400 is a universal-style, 4-amp Digital Sound Decoder with 6 function outputs. Designed for models with higher stall currents such as some S, O, and large scale locomotives; this decoder features easy-to-use terminal blocks for no-fault wiring and a higher audio amplifier for awesome volume, indoors or out. It includes an onboard connector for adding a CurrentKeeper (P.N. 810140) to maintain performance over dirty track and switches.
This is the revised Steam Decoder with the Steam2 sound set. The full list of sound can be seen on the Steam-2_Sound_Selections PDF