Lee I use to have a set of shark nose that said about the same thing I think seems it did say engine 910 your clear to leave not sure if it said track 10 thou. it also had engine revving noises it was a cool set it was in the B-unit I actually got a dummy a with that and bought the B-unit separate and got that in it then I saw another B-unit but it didn't have that in it just horn and bell these were all Williams befor Bachmann took it over.