Once I get industry profitable using road transport (best way is to deliver goods from one factory to three or four towns and supply that factory from one mine, sawmill or oil well (or one coal and one ore mine in that case), then I build a mainline railway connecting the towns and where possible passing the mines and factory. Build cargo stations in the towns and next to industry and where it is not practical to reach industry, build a cargo station as close as you can to the industry, then have your road vehicles deliver to the station (or from the station to the industry). So long as you have a rail link to the factory, materials will be delivered to your station for onward transport by train. Works really well and is profitable.
I then run mixed freight trains with cars to take goods and raw materials and then have the trains stop at all cargo stations along the line. This way they pick up and drop off cargo or goods in both directions, maximizing profits. I also use the same lines for passenger trains and usually build passing lines at cargo stations so the passenger trains are not stopped waiting for a coal train to load and unload. My fave approach to doing this is to build a single track cargo station with a bit of line out of each end, then run two parallel tracks, then place a second one track station on the opposite side. I give them both the same name and group them. To ensure the stations are on the same level, I use a bit of road first placed level to flatten the area (and I wish there was a flatten terrain function instead).
Once your cargo trains are running, then I delete any competing road lines (makes no sense to compete with yourself) no matter how profitable the road line is (the train line will pick it up really fast). Just make sure you have decent frequency on your train lines – every 5 min or better seems optimal.
Tip: build your factory to city cargo line connections first. There has to be demand for the raw materials to want to transport.