JOHNSON CITY, TN -

It's full steam ahead for the Carter Railroad Museum as it celebrates modern railroads on Heritage Day.

The trains may be toy-size and the structures may be tiny, but they represent what railroads look like across the country.

The museum holds a Heritage Day the last Saturday of every month and picks various themes by railroad or region.

Museum director Fred Alsop said the exhibit featured modern trains and equipment from large North American railroad systems.

"Today we're celebrating modern railroads. Earlier in May was National Railroad Day, and so they get out all the modern stuff, the Amtrak stuff, the big locomotives that are running on the rails today," Alsop says.

The model railroads are all operated by volunteers from the Mountain Empire Model Railroader club.

The Carter Railroad Museum is open every Saturday from 10 a.m. to 3 p.m.

Admission is free, but donations are welcome.