A locomotive can haul over 10,000 tons of cargo, but how heavy is the beast itself? Depending on the model, it usually weighs between 80 to 150 tons. But how do we weigh it? Just drive it onto a giant scale? It’s actually far more complicated than that.
(Video of the weighing test)
Round 1: Checking the Total Weight
A locomotive can't step onto the scale on an empty stomach. It must be fully fueled, topped up with water, and fully equipped with all necessary supplies—basically, in its absolute "full-strength" working condition. Once it rolls onto the weighing platform, we check if the total weight meets the standard. If it does, it passes the first test!
Round 2: Measuring Axle Load
Think we're done after checking the total weight? Not even close. Hundreds of tons of weight rest entirely on the axles. The load each axle bears is called the "axle load." Only when the axle load is sufficient can the wheels grip the rails firmly and provide enough traction for a stable ride.
Yet axles do not naturally share weight equally. Wear and tear, assembly errors and years of jolting lead to uneven load distribution among axles: some axles bear nearly breaking loads, while others barely carry any weight. When running at high speed under full load, such imbalance will be amplified instantly, resulting in wheel slip, deviation and braking failures, and sharply raising safety risks.
What is the solution? Measure pressure for every single wheel individually. High precision sensors are hidden beneath the weighing platform, giving a clear reading of each wheel’s load. Adjustments are made one by one until every axle bears balanced load and all indicators meet requirements.
In essence, this weighing test is ostensibly for measuring weight, yet in practice it serves as a pressure check up for the wheels. Only after passing this test can the locomotive run steadily and reliably on the tracks!
