Model Railroad Operation: TAC system

I have been thinking a lot about my SVNO and Model Railroad plans as of late.

It seems that the most common way for model railroaders to 'operate' their model railroads these days, is to utilize a 'car card' system. This is a system which closely follows prototypical operations, and includes cargo type, and equipment cards, for each rail car on the layout. As well as waybills listing where the car came from, and where it is going. Very detailed, yes.

But the type of operation I was used to when I was growing up, was called the 'tac' system as far as I knew. But I can't find any reference to this anymore.

The 'tac' system used colors to represent different industries and sidings on the layout. And, in turn, a box of thumb tacs, painted to represent each car parking spot on the layout, based on the color of the industry that spot is located in. Also, many extra tacs painted for outbound, or staging destinations.

At the beginning of the session, the dispatcher/yardmaster would collect all old tacs from the layout (excluding the yard), and place them in small boxes (sometimes sorted boxes, based on the car type). Then they would go through, and randomly pick out a thumb tac, of an unknown color, and place it onto each car. The cars would have small holes drilled into the top of them, where the thumb tac would stay. Once complete, the railroad is ready for operation.

Each operator is responsible for different colored industries. So lets say, the Mine run will work Luna Mine (pink), and the Scajaquada Mine (green). But it will also work the lumber yard (brown) between them, and the scrap metal yard (dark red). But the port run will work the port (blue), the warehouse district (orange, yellow, cyan), the lumber mill (purple), and the interchange track to staging (black).

The mine run operator will start off at the yard, after the yardmaster has assembled a train for him consisting of any cars with pink, green, brown, or dark red thumb tacs. The operator will take those cars and deliver them to their destinations, meanwhile he will pick up all the cars on his run, and in turn deliver them to their destinations as well, or leave them be, depending upon what color their tac is. If their thumb tac represents a color which the operator isn't responsible for, he brings them back to the yard at the end of his run, and they will get sorted for another operator to take. So for example, if the mine operator picked up a gondola at the scrap metal yard, with a blue tac, it would have to go to the port... So he would bring it back to the yard, so that the port run operator can deliver it to the port. But if that same gondola had a green tac on it, the mine run operator could just deliver it to the Scajaquada Mine in that same run. Or, if that gondola had a dark red thumb tac on it, it would just stay in place at the scrap yard.

Sometimes the thumb tacs for specific industries, with specialized sidings will have numbers printed on them to indicate the spotting location of the car once it is delivered.

This is a fun, and simple way to run operations on a model railroad. And I think it might be the way I choose to operate, at least at first.