The came through our yard 3/31/03.
The tarps have zip-outs at places for cab, handbrake, etc.
From what I could tell they wore UP colors.
Maybe it's like cars they want to keep the new models secrete.
Those would have been unpainted SD90Macs coming from the GM Electromotive Division in London, Ontario... just north of where I live... I remember them being built and periodically sitting outside the plant last year...