All three engines feature a Soundtraxx Tsunami decoder and multiple speakers. The lead BNSF unit features a 28mm square HB speaker in the cab and a medium oval speaker in the radiator section. the Union Pacific units have 1.1" round speakers in the cabs coupled with 34.7mm x 20mm oval speakers.
All three are remotored with a Kato drive. Next up for these locomotives are improved lighting effects with led's.