Might be a stupid question but what was the purpose of the hump yard and what was it about the yard that had wagons on the side saying "Do not loose or hump shunt"?
For a start:http://en.wikipedia.org/wiki/Classification_yard
And more specific to us:http://users.vic.chariot.net.au/~ser567/melbyard.html
- A train would arrive into the arrivals yard, located west of North Melbourne station. It is still in existence today for spark and V/Line stabling, along with miscellaneous freights.
- Someone would walk along the train, write down the wagon numbers and the wagon destinations, then send them over to West Tower
- The consist would be entered into a computer
- The hump engine would couple onto the down end of the rake of wagons, then push them towards the hump
- Each wagon would be uncoupled as they rolled over the crest of the hump
- The computer would operate the points leading down into Melbourne Yard, tracks were grouped into 4 balloons (A, B, C and D), with each track dedicated to a specific destination
- The wagon would roll down the hump, getting directed into the track for the final destination
- Brakes called 'retarders' were located along the tracks, these would slow down wagons as the rolled, so they didn't go too fast and crash into wagons already in the destination track
- Each other wagon would get pushed over the hump, the computer flinging the points over to send the wagons to the correct spot, and operating the retarders to control their speed
Once everything was over, a loco would go to each track, and made up a trains as required, which would then depart to wherever they were headed.
The 'trimmer' was a loco that sat around until a wagon was sent into the wrong track from the hump, it would then go off and shunt the wagon into the correct track.
"Do not loose or hump shunt" means the wagon was fragile or carrying something fragile, and could not be bumped around. As for loose shunting:http://ukhrail.uel.ac.uk/glossary/gl-l.html
A process of shunting in which a vehicle, which is not coupled to the shunting locomotive, is propelled forward and then allowed to continue moving under its own momentum. Also known as fly shunting.