TT Scale (1:120) 50 Ton Bettendorf trucks based off of Southern Rwy. truck drawings. Designed around 7mm diameter wheel sets with 18.5mm pointed axles. Link to wheel set supplier https://www.shopssl.de/epages/es124766.sf/de_DE/?ObjectPath=/Shops/es124766_radsatz/Categories/TT__Radsaetze_RP25. Wheel set have slight tight fit and will required final bearing journal reaming for smooth free rolling. Trucks material in photos are Frosted Extreme Detail.