Comparing a render of the set 133 locomotive with my actual copy, I noticed a difference: a black 1x2 brick between the wheels on each side. Thinking that either my actual train or the ldraw file is wrong I checked the instructions again. And I (...) (20 years ago, 28-Sep-04, to lugnet.trains)
(...) Perhaps the 1X2 brick fell off between assembly and the photography session beings it appears it's held on by just two studs from the under side of the plate. -Patrick (20 years ago, 29-Sep-04, to lugnet.trains)
(...) I think it is more a design change between the cover photo shoot and the creation of the instructions. Most other examples (e.g. 721 and 8860) have used new parts in the instructions and the set itself which were probably not yet available (...) (20 years ago, 29-Sep-04, to lugnet.trains)