The Workcart is a vehicle used to navigate through the Freight Transit Lines. It spawns in the side tunnels of each stations which you can find by going through the doors with the bright green "Maintenance Room" sign. The Workcart has armored plates that protect you from bullets. Crouching behind it will keep you safe.
The Workcart has 3 speeds: Low, Medium and High. Press W to go forward and increase the speed. Press S to reverse and decrease the speed. (going high speed and holding S will brake the Workcart, causing a very sharp noise on the wheels)
There are multiple barricades that spawn on the tracks, ramming into the barricade will destroy it. However, going high speed and ramming into the barricade may damage your Workcart, the screen on the driver seat will display a red "WARN" text when your Workcart is going high speed and a barricade is in the way of the Workcart.