Heljan 1151 OO Gauge Class A Tank Wagon ESSO No.4021 (grey with ESSO PETROLEUM lettering on barrel)
Model of the 35-ton glw (approx. 22 tons payload) oil tank wagons introduced around 1960, following on from Heljans' models of these wagons in O gauge.
The 35-ton glw wagons were equipped with suspension and vacuum train brakes suitable for running at higher speeds than the older 12-ton 4-wheel tank wagons, allowing block oil trains to travel safely at increased speeds.