One of our latest investments was this mini vacuum cleaner. It is powered via a USB cable, but there is a battery version as well.
It was originally intended for cleaning PC keyboards but it is perfect to clean model train tracks as well. It is strong enough to remove grass, dust etc. from the tracks but not so strong that it would "swallow" figures or cars. The brush has a diameter of approximately 1 cm so you only clean where you really want to.
I can really recommend it to all model train layout builders!
Previous posts:
Part 1: The Christmas present
Part 2: The petrol station
Part 3: How it all started
Part 4: My model car collection
Part 5: The farm
Part 6: My GDR collection
Part 7: The base plate
Part 8: Basic electricity
Part 9: Mounting the tracks
Part 10: DR railroad cars
Part 11: Electrifying the railway switches
Part 12: Electricity for the lights
Part 13: Another DR passenger car
Part 14: An electric drive for the second railway switch
Part 15: My website "scalemodel.photography"
Part 16: The self-made protective pad
Part 17: Moving the base plate to the final position
Part 18: The campground
Part 19: The petrol station and the farm
Part 20: The railway crossing
Part 21: Our PIKO Junior set
Part 22: Creating a charging station for electric cars
Part 23: The Flemish houses
Part 24: More street lights
Part 25: Interior lighting for the farm