Freight railroads by definition are non-socialist because they (even the NWP) have to make enough from operations to at least meet the payroll. A bit more is useful if they intend to make payroll more than once. Regardless of who actually owns the tracks. Ideally, they make enough to cover capital and track maintenance costs as well, but if the line is publicly owned or otherwise maintained for other reasons by others that part of the cost structure might be lower.

Passenger railroads as transportation services (i.e. not pure tourist trains a la Roaring Camp) are by definition socialist because they can't make payroll and other costs completely from fares that people can afford to or are willing to pay. Tax or other subsidies cover the additional cost because the service provides value that fares alone can't cover. In the case of publicly owned/operated services that may be macroeconomic or social-welfare concerns justifying use of tax funds; for private operations it may be advertising value or be required in order to maintain a franchise or by regulation (e.g. pre-Amtrak).

I wish the SC folks well with generating freight traffic. It's a great way to maintain a line while holding it for other purposes at minimum cost to the taxpayers, and maybe it could even be used to support economic development of a conventional sort.