MTH Premier NJ Transit ALP-46 Electric Engine 20-5661-1 is listed on line as 1:43.5 scale and operating on O-72 curves. Length is 16-3/16 inches. Just for comparison, the MTH Premier New Haven EP-5 electric locomotive (20-5531-1) is listed as 1:48 scale and operating on O-42 curves. Its length is 17-7/8 inches. The ALP-46 has two two-axle trucks and the EP-5 has two three-axle trucks with longer truck wheelbase. Of course, they both run on 3-rail O-gauge track with rail spacing of 1-1/4 inches.
Based on the length and number of axles, it would seem that the ALP-46 should run on smaller radius curves than the EP-5. However, looking at the MTH on-line images of these locomotives, the ALP-46 sits lower on the trucks (no visible gap between body and trucks) than the EP-5 (clearly visible gap between body and trucks). Therefore, it may be that the ALP-46 trucks cannot pivot through as much of an angle as the EP-5 trucks due to potential interference with the body. Thus the ALP-46 is listed for O-72. This is just my conjecture. You need to check with MTH or a dealer.
MTH European electric locomotives are made to larger scales (1:43 and 1:45) than American O scale models (1:48). The MTH ALP-46 at 1:43.5 is approximately 10% larger than if it had been made in American (1:48) O scale. I don't think this is the reason for the listed O-72 curve requirement but it may be a contributing factor.
I own several MTH Premier electric locomotives with PS1. (New Haven EP-5s and New York Central P2s). They have been excellent runners for twenty years.
MELGAR
