I'm no expert on how taxes work on railroads but I can offer what I have picked up on bits and pices on the subject.
Railroads pay taxes on the property that they own. Some states like NY charge the same tax rate on the property weather there is rail on it or not there are no brakes on RR Property there. Other states slash there taxes if the property is abandoned with or with out the rail on it if the ROW still remains in the RR Name. But still a railroad can lease the rail they use if its owned by the county's or the state as well there for releveing them of paying taxes. There would be property taxes on buildings I they would vary from state to state on the taxes on them as there most often built on the ROW.
Most of the larger railroads lease the locomotives that they operate I would think that there is no tax on them unless they buy them out right. Smaller railroads tend to buy used locomotives and on occation new ones there for There would be a sales tax on them. Not all railroads own the cars that have Yes they may have the road name and reporting marks of the R.R. on them but they might still be owned by the bank or leaseing company.
no matter the weather or the country I'll still be trackside!