Another point to consider are the three rules of real estate: location, location and location. The Strasburg is located in one of the top tourist areas in the country. There are also millions of people within an easy drive of Lancaster.
Many early tourist railroads were set up because someone was able to obtain an abandoned branch line in the middle of nowhere. Most struggled for a few years and then folded. Once everyone within driving distance had visited, there was nothing to bring them back. There is a reason why amusement parks open a new major ride every couple of years. Hard to do with a tourist railroad.
Michael Allen