Hi Keven,
Both the Black Hills central and the Nevada Nothern are both quality railroads. I have concidered working for them both. perhaps some day I just might. You stand to learn alot about steam on either line and I wish you the best of luck. The biggest differents between the two, other than senery is the Black Hills Central burns fuel oil while the Navada Northern burns coal.
As it stands today in the tourist Railroad industry, finding and keeping new people who are jazzed about learning and working on steam is a rare commodity. Finding experienced or qualified steam people is even more in demand. The truth is steam railroading is hot, heavy hard greasy work. The pay is usually low. Not to mention the job is usually very seasonal. It is truly a dying industrial art. You also must be willing to relocate for the job. Most people will usually find easier work that pays better. A computer job comes to mind. I can say that at least the view from a cab window is constantly changing unlike the view from an office cubical.
good luck and go for it.
yours in steam.
Phil Reader.