A cowcatcher, also known as a pilot, is the device mounted at the front of a locomotive to deflect obstacles on the track that might otherwise damage or derail it or the train.

In the UK small metal bars called life-guards, rail guards or guard irons are provided immediately in front of the wheels. They knock away smaller obstacles lying directly on the running surface of the railhead. Historically, fenced-off railway systems in Europe relied exclusively on those devices and cowcatchers were not required, but in modern systems cowcatchers have generally superseded them.

Instead of a cowcatcher, trams use a device called a fender. Objects lying on the tram track come in contact with a sensor bracket, which triggers the lowering of a basket-shaped device to the ground, preventing the overrunning of the obstacles and dragging them along the road surface in front of the wheels.

In snowy areas the cowcatcher also has the function of a snowplough.