Proto 3 Steam and Diesel/Electric Upgrade Kits. The kits must be installed by an MTH Conversion Center or Service Center. Warranty valid only with installation by an Authorized Conversion Center.

MTH Proto-Sound 3 Upgrade Kits
MTH Proto-Sound 3.0 Upgrade Kits for Steam, Diesel and Electric 3 Rail Engines. Convert most 3 Rail O Gauge Locomotives with DC Can Motors and a flywheel to MTH DCS Command System. We are an MTH Authorized Service Center and Upgrade Center. We will also repair your MTH locomotive even if it was not purchased from us. Call or email for details.