Gas return railway car hydraulic cushioning unit and method of converting a spring return unit

摘要

A railway car hydraulic cushioning unit prevents the mixing of gas and hydraulic fluid in chambers interiorly and exteriorly of a high pressure cylinder unit by strategic placing of metering ports through the cylinder wall at positions below the level of gas in the exterior chamber. The invention is furthermore directed to a method for converting hydraulic cushioning units adapted for connection to an external spring operated restoring mechanism to a self-contained gas return unit.