What kind of internship? One that is connected with your studies? And what is your studies?
This sounds like a museum profession or history degree project. Your best resources will come from existing museum or preservation organizations -- AAM, ARM, AASLH and then regional, state and local organizations.
But some basic questions to answer in developing the displays and their theme are the following:
1. What is the story that you want to tell? Is it the story of railroads in this particular community, in the county, in the area of the state, or the whole state of Texas?
2. Who is your audience(s)? Local residents, travelers, school (elementary) students, or whom?
3. Is this going to be a permanent display, or a changing exhibit?
Keep in mind most people have a short attention span. Keep the displays simple, the paragraphs and sentences short. Use illustrations that tell a story just by their imagery.
A typical display panel technique is to have a title panel that conveys the story element you want to tell. Then tell the story in more detail in the subsequent panels. Some people will only read the main panels; others will stop and read all the panels.
Talk with staff people in nearby history museums that seem to be doing a good job in their specialties. It may not be what you're going to present -- but the techniques and advice will help yours. Get their recommendations as to information sources and other resources.
For an interesting and well done display in Texas, visit the second floor of the former Santa Fe depot and division office at Temple, Texas.
A suggestion is to contact Bob LaPrelle at the Museum of the American Railroad (formerly Age of Stream) in Dallas. He is their executive officer; also he is currently serving as President of the Association of Railway Museums. The Dallas museum is busy planning for a move to the city of Frisco and a (hoped for) major building project, but I'm sure he can point to toward resources.
Another resource in Texas might be Mary Irving at the MARTIN & FRANCES LEHNIS RAILROAD MUSEUM of Brownwood, Texas. She was once with the Museum at Temple and has a long history with local history museums and is aware of railroads. I first met her probably a decade and a half (or more) ago when the California State Railroad Museum was holding annual railroad history symposiums.
Brian Norden
member, Board of Directors, Orange Empire Railroad Museum
former Secretary and later board member of Association of Railway Museums.