Fly system By trimming the lift lines, loads are more evenly distributed to them. Turnbuckles are moused (secured against free rotation) to prevent the jaws from slowly unscrewing over time due to vibrations incurred during normal use. Counterweight lift lines typically connect to the tops of arbors with shackles. A block is a pulley used to support and direct lift and operating lines. A block consists of a grooved wheel, known as a sheave (pronounced "shiv"), steel side plates, spacers, shaft, flange bearings, mounting angles and clips, etc. Blocks are sized based on anticipated live loads, operating speeds, line type and other
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