The Amfleet I and Viewliner II cars from Golden Gate Depot are some of the finest Amtrak models available in O Scale, but some cars might need a little tweak out of the box in order to mount the side steps properly.
On the side of each car end are two holes for the add-on steps; the larger hole accepts the step sprue and the smaller hole accepts the miniature screw. The screws are quite tiny (extras are provided), but on some cars the screw does not thread in easily... or at all. Forcing the screw does not work well because the threads easily strip; at best the steps will hang loose with the screw protruding. Fortunately the repair is very easy - the hole must be rethreaded with a hand tap. A M1-0.25 hand tap with corresponding handle are all that is needed to repair the hole; both items can be easily found online for nominal cost.
To perform the repair insert the tap into the handle, insert the tap into the hole, then turn the tap handle a few times clockwise to engage the tap in the hole. Continue turning clockwise slowly until the tap point protrudes from the back of the step. Some minor resistance when turning is OK (a sign the tap is cutting/reshaping damaged threads), but too much is a sign of trouble. The tap can break if too much force is applied. Once through rotate the handle counterclockwise to remove it from the hole; some fine metal filings might be on the end of the tap, but this is normal. Reinstall the step and drive the screw in; it should thread with minimal resistance.
M1-0.25 screws can be found online or from specialty retailers for a few dollars (for a pack of 100+ screws). The original screws are 2mm long, pan head Philips with a black oxide coating; slightly longer (3mm) screws and/or different finishes also work, but countersunk head or self-tapping screws will not work for this application.
Hope this helps!