I have a Hampton Bay track light I took from my previous home and I want to install it above my sink in the kitchen of my new home. The track the lights slide into is too long to fit in the area. Can you cut the track to shorten it or are the electrical units inside this unit?

Yes it can be cut. I would leave it as it is and cut it. Make sure you cut it perfectly square.
After you cut it remove the dead end cap and replace it on the new cut piece.

Please let me add a qualification, please.

Yes, if the product's manufacture tells you that you can do that. Read the instructions or go on-line and see if they have published the instructions.