Portals aside for the moment, the TLR system is built on top of the older interactive industries/interactive rolling stock/commodities/waybill system. So some of the old rules still apply. For example...
Industries must be setup to produce and consume commodities.
Rolling stock needs to be available on the route that can carry the different commodities being produced and consumed by the industries.
Industries will stop producing if they run out of the commodities they consume. For example, the coal mine needs Diesel Fuel to produce coal.
When an industry queue for a product that it consumes is full, it won't accept any more deliveries.
Now from my play with the TLR system, it examines all of the above conditions and pairs up industries that produce a commodity with an industry that consumes that commodity and creates a task for a driver to carry out. If any of the above conditions are not valid then the task can't be created. For example, if there are no hopper cars to carry coal than no tasks can be created to pick up or deliver coal. Or if the coal mine runs out of diesel fuel than once the coal supply drops beneath a certain level than no tasks will be created to pick up coal even if the hopper cars are available. A really sticking point here is the rolling stock part of the equation, not all rolling stock will carry the commodities being used by all industries. When you are setting up a session, care must be taken to match rolling stock that can carry to the same commodity used by the industries. For example, the coal mine is producing standard Auran coal but the hoppers cars you are using can't carry Auran coal but can carry a coal commodity made by RRMods. A task can't be made to use those cars to pick up the Auran coal. So as always, a certain of planning and tweaking is required to get everything in balance within the session before TLR is enabled.
