The prototype the cars was built by the Southern Railway in the Spencer Shops for MOW service in the early 1950's to the 1960's. The cars have gate on the sides that could open and 4 rails with 2 different size gauge rails inside for the crosstie kicking machine that could kick ties out the cars to stage the new ties for tie replacement jobs. These cars made it in the Norfolk Southern era until 1994 and then a year in 1995 all those cars gotten replaced with the newly rebuilt Norfolk Southern M-271's and M-272's MOW Crosstie Gondolas. This HO 1:87 HO Southern Railway 50-Ton Crosstie Car Pack STL files comes with the body A, B and tall and coupler box covers. Also it's gonna have the first time speical future add on updates by me at no cost after purchasing this pack. The speical adds ons is gonna be the Southern Railway 50' Speical Tie Kicking Machine Flatcar and the Tie Kicking Machine itself. The only thing you need to complete this model is some 50-Ton bettendorf trucks or some 70-Ton rolling bearing trucks with 33' metal wheels and metal couplers for the era of your choice. Also you need 2-56 x 1/4 phillips pan head screws for the trucks and 2-56 x 1/8 phillips pan head screws for the coupler boxes. Note these STL files is for personal use only and not to be commercially reproduced!!!