As long as you are stopped, you should get credit.
Time yourself (you should have a stopwatch, or at the very least, use your phone) and make sure you get credit when you get back.
Last time I counted, I lucked out and had a train every day. Most days I waited 1 - 3 minutes. But one memorable day, it was 13 minutes.
Don't leave money on the table.
Once your route is populated, stop signs, railroad crossings and the like will have a weighted value and will count into your new eval.