I purchased a few MDC-Roundhouse 50' boxcars. I plan to replace the MDC trucks with MTL trucks with couplers. Will I have any problems changing the trucks?
I haven't had any problems converting them. There have been times where I had to trim the car body so the coupler pocket can move smoothly. A shoe-in for the most part.
You'll need to use the pins in the MT packs that aren't the two together on one bit of sprue, other than that they work fine. Put MT trucks under 3 MDC cars today!
I have done both, added MTL trucks under some cars (older ones, high cubes and reefers), and used body mounted MTL #1027 on the new PS 50' box cars (those with trucks with metal wheels). Both conversions were easy and the results work well.
I've swapped out quite a few MDC cars with better couplers. I've used both MT and Accumates (no decision on which I like better yet). Anything is an improvement over the Crapidos though.