truck and track![click to hear](/images/speaker.jpg)
The most up-to-date subway trucks ride on tires, which provide fast acceleration and little noise or vibration.
invert ![click to hear](/images/speaker.jpg)
Thick concrete foundation for the tracks.
runway ![click to hear](/images/speaker.jpg)
Metal or concrete track that is fixed to the invert on which the tires roll.
running rail ![click to hear](/images/speaker.jpg)
Regular railroad rail for the steel safety wheel to roll on in the event the tire deflates; it also receives the traction current from the return shoe.
guiding and current bar ![click to hear](/images/speaker.jpg)
Metal bar against which the guiding tire rolls; it also supplies the traction current.
inflated guiding tire ![click to hear](/images/speaker.jpg)
Tire mounted at right angles to the carrying tire; it rolls against the guiding bar to guide the truck.
inflated carrying tire ![click to hear](/images/speaker.jpg)
Nitrogen-filled tire that supports and conveys the car.
steel safety wheel ![click to hear](/images/speaker.jpg)
Auxiliary regular train wheel that comes in contact with the running rail in the event the tire deflates and during switching.
sliding block ![click to hear](/images/speaker.jpg)
Shoe taking the current from the guiding and current bar.