Keeping track and wheels clean is a necessary evil, especially when running long trains. I spend hours cleaning car and loco wheels in prep for a video, also don't forget a small drop of oil on the axles. On postwar wheels 1 drop per wheel works, but since prewar wheels are mostly hollow, that is 2 drops per wheel, 16 drops per car.....time consuming, but pays-off in improved performance.
Now for track, the black gunk builds-up no matter how clean you keep the wheels. I wipe the areas I can reach with alcohol, isopropyl not Jack Daniels, and put a cloth on a yard stick for the harder to reach areas.
You can do a certain amount of track cleaning while operating with a track cleaning car. Lionel's 3927 may work on a small layout, but is inadequate for larger pikes.
I have several TC cars made by Centerline products, purchased about 20 years ago, so not sure if still in business. It is a heavy bronze block, hollow in center and trucks mounted to the ends, comes with MPC era trucks. There is a roller, similar to a small paint roller with caps on the ends that drops into the center well. You fill the roller with nuts/bolts or small rocks so it bounces around and add some track cleaner or alcohol (not lighter fluid.... too dangerous) to outside and push it around.
I modified a beater 2812 gondola, as shown so I have a "prewar" track cleaning car. A Marx generator and plastic tank are added just for looks. It works fairly well.