At about 9:30 a.m., the crew of Engine 53 is scheduled to do some training with Truck 50 at the Central Yavapai Regional Training Academy.
Truck 50, which has an aerial ladder, is a companion with Engine 50, but does not have its own crew. Like all Central stations, the firefighters take the vehicle - apparatus, in fire-speak - most suited for the kind of emergency call they get.
At Station 53, the "default" is Engine 53, which is the versatile pumper. Depending on the call, though, firefighters might instead respond in Patrol 53, which is intended for wildland fires; Water Tender 53, a massive tank truck that can bring a water supply to an area with no hydrants; or Utility 53, a truck loaded with gear for extended operations.
Because the firefighters are typically still "available" for calls while they train, the Engine 50 crew brought both their pumper and the ladder truck to the training ground.