Optic flow sensor test using train

Im an undergraduate engineering major at Drexel University and Im working on a research project. As part of the project, we need to test a sensor we’re using. We wanted to strap the sensor to a model train and have the ability to vary the train’s speed using a computer.

I am completely new to model trains and have had some difficulty picking up the lingo and sorting through train sets. I was hoping someone had suggestions for the following:

-An average quality, relatively inexpensive train set (looking to spend a few hundred dollars)
-A DCC system to control the train
-any other necessary equipment to interface the DCC with a computer
-any other equipment needed to run the train

Any help would be greatly appreciated.