As a speeder nut and collector as well as a CR nut, I have put hundreds of hours into researching CR speeders and have been able to find a total of 3. One was a former Reading car with a wood cab, the second was CR PD 1 for the CR Railroad Police (which I believe had a wood cab also) and the other was a non descript Fairmont MT-14.
Those three are the only ones I have found evidence of. By the time Conrail came around most railroads were disposing of motorcars. Fairmont was still making them, but the sales had drastically dropped in favor of Hy-Rail.