Draw-works block and traveling block pulleys for mechanical advantage. The line then exits the last sheave on the crown block and is fastened to a derrick leg on the other side of the rig floor. This section of drilling line is called the "dead line". A modern draw-works consists of five main parts: the drum, the motor(s), the reduction gear, the brake, and the auxiliary brake. The motors can be AC or DC-motors, or the draw-works may be connected directly to diesel engines using metal chain-like belts. The number of gears could be one, two or three speed combinations. The main
Electro-pneumatic brake system on British railway trains thereby activating the disc brake. The "presence" of the voltage holds the brakes "off", providing a Fail Safe system. The 3 step "Westcode" brake uses three wires and these operate in a binary sequence to control the brake step. 10 & 11 are the brake coding to provide the 3 steps, 12 wire is emergency brake, 15 wire is EP brake negative. Positions on the brake handle are: This system remains in use today. On the previous EP brake systems, if the train divided or a serious air leak occurred the drop in Brake Pipe pressure automatically caused the brakes