Something about the phrase $COMPANY Police just makes me uncomfortable.
I think it makes sense for railroads to have police, as the crimes that affect them are multi-jurisdictional by nature and specific to the railroad. Colleges are similar in many ways... US Marshalls + pinkertons provided security to railroads in the 19th century. Professional police alleviate many of the abuses that inevitably happen with security people.
I get a little uncomfortable with private police not tied to an institution. When I was in vacation in South Carolina, the resort rent-a-cops were sworn officers... that sounds like a way to cover up crime to me.
CSX: http://www.csx.com/index.cfm/community/csx-police-department...
NY MTA: http://web.mta.info/mta/police/
Norfolk Southern: http://www.protecttheline.com/ns_police.php
Canadian Pacific: http://www.cpr.ca/en/safety/cp-police-service
These companies exist to be able to operate at a loss to serve a greater benefit to the public, but giving them more power than that doesn't really seem like it would be in the public's interest.