Re: San Juan Extension and profitability

This is really an interesting subject, but it gets complicated quickly.

As George noted above, the technology and the economics changed dramatically with the introduction of good highways and motor carriage. But at the risk of a whole lot of oversimplification the ICC prevented the railroads from taking advantage of that revolution and substituting trucks for rail where it was more efficient. Branch lines, both standard and narrow gauge, were required to remain in service long after it was clear they cost more to operate than the parallel truck routes. Railroads were expected to subsidize the money loosing lines from the profits they made on the profitable lines, in the name of "public convenience and necessity".

Then there was the challenge of evaluating the "profitability" of any line segment, narrow or standard gauge. A large proportion of the costs and revenues are shared with other parts of the railroad, and the variability of costs often involves both time and step functions. And the rates and divisions that determine a lines revenue have their own complexities. Which is not to say it can't be done, but it usually involves a lot of assumptions and judgement. So there was a lot of room for argument over what lost money and what didn't, depending on your assumptions.

And finally what exactly is "public convenience and necessity".

A good subject for a book...actually several books.

JBWX