I ate at one of the oldest diners in the US, located inside a 1920s railcar. It was worth the hourlong wait for a seat.

Erin McDowell/Business Insider

• I recently visited Palace Diner in Biddeford, Maine, which is nearly 100 years old.
• I waited over an hour for a spot at the diner's 15-seat counter but thought it was worth it.
• However, I had to return the next day to try a famous menu item that had sold out before I sat down.

On a road trip from Connecticut to Portland, Maine, I stopped off at Palace Diner.

The almost 100-year-old restaurant is famous for two things...