I can't talk about the details of any agreements, of course, so I have no idea if the PCC ones were valid or not, but given the players, I'd bet lots of money they're valid. In general, however, it works like this:

The original line lease or Interline Marketing Agreement (IMA) that spins off the short line will contain various provisions which outline the short line's rates, car hire relief, standards of service, and tariff provisions.

For example, it'll have a table of commodities and station zones which will have different rates: Lumber & forest products zone 1 is $200, zone 2 is $250. Chemicals at zone 1 are $300, zone 2 is $375. Stations XYZ and ABC are at zone 1, etc. You get the general idea.

There will then be sections outlining the types of accessorial services and incidental charges, like respots, special switches, error delivery, setback charges and so on which will be part of their tariff. There will then be a separate section talking about what kind of car hire relief will be given, if any, and how that works. The better ones of these, in my opinion, are actually outlined in tariff format.

They'll also have parts saying the short line has to exchange certain kinds of EDI messages, report to TRAIN II in a timely manner, and so on.

As part of this description, it will usually have something which roughly says that these charges and only these charges may be applied. In particular, they will usually mention fuel and other surcharges applied against the customer as being prohibited.

Sometimes it says they can't be applied at all, sometimes it says they can only be applied with the Class 1's permission, and other times it doesn't say anything. It all depends on who wrote the agreement and when.

Again, making more gross generalizations, the more recent the spinoff the more detailed and restrictive the IMA. The whole point is that the Class 1 wants to ensure they retain full rate authority to their customers. If the short line is adding surcharges against the customer, that's basically making a rate.

The line between what is a charge for movement of freight vs. added service can be vague sometimes, but in general if it has to just moving the car the same as for all customers then it is considered part of the freight rate and off limits to short line surcharge. If it is an extra service, like a respot, then it is something the short line can charge for.

Again, these are all generalizations, your mileage may vary.