Bike parts will still be needed as bikes become a major source of transportation. electrical wiring will still be used as many will still attempt to produce wind and solar power. you will even see some radio/shortwave communication. I think there will be a big market for "hand crank" equipment repairmen (radios, lights etc)
blacksmithing will make use of abandoned seel.. even entire buildings.
large industrial machinery will be salvaged to make windmills, waterwheels, and other basic powered machines. I think there will good business for those that can make wagons from scratch. as for other remnants.. people are quite resourseful.. eventually everything will be repurposed, or returned to operation. nothing like the deadly scale it is now though.