What would be a good estimate of the minimum amount of cars shipped and/or received on the branch per year needed to pay for the maintenance on a mile of the track given the following?
Located in California
Flat, stable geography
About 11" of rain per rain, almost all in winter
Temperatures reach freezing point a few times per year
100+°F fairly common in summer
6a) 220000 pound gross car weight
6b) 286000 pound gross car weight
6c) 315000 pound gross car weight
Heaviest locomotive is a GP38-2
Most loads are outbound agricultural products with the possibilty of inbound lumber, paperboard, minerals, fertilizer,and grain.
You might get Mudchiken to float an answer. The only one I have is not based on the amount of traffic, but a book that I have on short line operation published back in the middle 1980’s “prior 315,000” — $3000 to $10000 per mile depending on how good of shape the roadbed and track structure is in for the first 10 MPH (Class 1). It goes up from there. The better the shape, the less per year it will cost the short line. How many cars that equates to depends soley on the rate division your line haul connection(s) will give you.
If you can crib the entire line, your costs will drop. These figures include labor for the overhead positions (your Mudchickens), no new rail and only enough new ties to keep the track in guage. Surface? What surface!
My rule of thumb is 100 cars per mile per year. Presumes your revenue and costs are such that you can put $75 to $100 per car into the line. Will keep whatever class of track you have in terms of ties, and a bit of ballast. No rail relay. No bridges. You get paid for private crossing work.
There is another “cars-per-mile” rule of thumb that I learned from an old Agent back in the middle 1960’s – 1 car per mile per day. It would cover all costs and an adquate ROI during that time period.