Someone mentioned the size of the hoses on these in an earlier thread but I never followed up and lost it. What is the consensus about the size of these as evidenced in Matt's nice photos above? Are they too large? (sure appear to be..)
You're right, c.sam . . . they are large. In real life, the m-u hoses (on each side of the coupler) consist of three hoses on locomotives equipped with electrically-controlled sanding, and five hoses on those with air-controlled sanding. The main reservoir hose -- furthest inboard of the three --is of a larger diameter than the others, but is not as large as the brake pipe hose (next to the coupler). The application and release pipe and actuating pipe hoses (and the sanding control hoses, if equipped [one for forward, one for reverse]) are of the smallest diameter*. I don't know the actual measurements. Note: Although there is piping for m-u hoses on both sides of the pilot, some railroads have been thrifty with the hose budget, and only apply hoses on one side. This results in a lot of bad language when employees have to unscrew hoses and move them to the other side when coupling locomotive units.
The glad-hands of all the m-u hoses are the same, and hoses can accidentally be crossed with each other, but the brake pipe hose glad-hand will not couple to the m-u hoses. The train lined main reservoir hose is thicker because of being built stronger to withstand constant140 psi air pressure, and has a larger interior diameter because of the rate of flow required to charge the brake pipe after a train has been assembled and is being readied for an initial terminal air brake test.
* Most first-generation diesels had air-controlled sanding, but, as years passed, many were converted to electric control (through two of the pins on the m-u receptacles and jumper cables). With both systems, sand is blown by compressed air, through the sand pipe, to the wheels. The difference is in the way the sanders are controlled.
