Union Pacific Railroad (U.P.) class 4000 "Big Boy". Locomotive no. 4013 as it was around 1960. High-efficiency can motor with bell-shaped armature and flywheel in the boiler. 8 axles powered. 4 traction tires. Articulated frame to enable the locomotive to negotiate curves. Boxpok wheels. Center driving axles are spring loaded. Maintenance-free LEDs for the headlights, tender light and number boards. Coupler hook can be inserted into the pilot. Close coupling between the locomotive and tender. Steam lines can swing out with the cylinders. Separately applied metal grab irons and railings. Many separately applied details. Can be retrofitted with 2 Märklin 7226 smoke generators. With 2 digital decoders, controlled high-efficiency propulsion, sound generator and additional auxiliary functions. Headlights, and smoke generators that can be retrofitted on the locomotive work in conventional operation and can be turned on and off digitally. Length over the couplers 46.5 cm. Total weight with box is over 2,5Kg. Tested and working. The wooden box is Marklin original. Interior foam was replaced as the original was rotten over the years. Look carefully at the photos, they show the condition of the items and are part of the description. Will be carefully packed and shipped by registered post.