Abstract: This disclosure deals with a hydraulic cushioning unit for a railway car, including a gas return. The unit includes a main reservoir which is precharged with a hydraulic oil and an inert gas. At least one reservoir extension is also provided at the upper side of the unit, the extension enabling the unit to be charged with relatively large amounts of oil and gas. The oil volume when the unit is in its neutral position is approximately 76 percent of the total reservoir volume, and the reduction in the gas volume during impact conditions is not more than approximately 40 percent. The unit includes a tube and two separate charging passages for precharging the unit to the desired oil and gas volumes.