What is the consequence of a ruptured control (service) line?

A ruptured control or service line results in a loss of air pressure that is crucial for the operation of the trailer's braking system. In standard air brake systems, the service line is responsible for transmitting air pressure from the tractor to the trailer, allowing the trailer's brakes to engage appropriately when the driver applies the foot brake.

When the service line is ruptured, the trailer loses its supply of air pressure, leading to its brakes not functioning at all. This means that the trailer can't slow down or stop effectively since there is no air to activate the braking mechanism. The tractor may still have functional brakes since it is independently powered, but without the trailer's brakes, there could be serious safety hazards during operation. Understanding the implications of a ruptured service line is crucial for maintaining overall vehicle control and safety on the road.