I am curious about the numbering system as using number and letters was only just being introduced when I finished up.
So does 3MP9 equal 3 as in Victoria, M + Melbourne, P + Perth and 9 is the train number?
That show was the first time I had ever seen a 'Tippler' in action as I thought they had to uncouple the vehicles which would slow things down but instead the coupler 'Rotates'.............ingenious.
I'd still like to see which is the better and fastest, Bottom Drop or Tippling, and why one is chosen over the other
The ARTC numbering system is explained in this pdf http://www.artc.com.au/library/Train_Numbering.pdf
Basically the first number is day of departure (1=Sunday - 7=Saturday)
First letter is Departure location, second letter is destination
Fourth digit is described by ARTC as a departure sequence for a particular day, however it appears to now indicate the operator.
it seems all SCT train have the 4th digit as 9
(as a note the digit 8 denotes a passenger train)
So your example of 3MP9 would indicate Departing on a Tuesday (3) from Melbourne (M), to Perth (P) and operated by SCT (9)
Rotary Tippler v Bottom discharge -
It all comes down to total cost
Bottom Discharge wagons require multiple sets of doors on the bottom to enable discharging.
Door maybe manually operated or automatic operation.
Manual require a human to open and close the discharge doors which restricts the train speed through the unload shed
Automatic operation require a costly control system (usually Pneumatic) to open and close the doors so wagons require pneumatic piping and a loco to supply the compressed air to operate the doors.
Over time bottom discharge wagons require ongoing maintenance on the doors and operating system
This all adds up to Dollars for ongoing maintenance
Rotary wagons do not require bottom doors as to unload you tip the wagon over.
So only a rotary coupler is required at one end of the wagon
Obviously the Tippler is a lot more expensive to build than a simple under rail bin
So one system has higher cost per wagon, the other higher cost for unload system.
Which is better? good question.