Currently, Relay is a historic district of Halethorpe, Maryland, with attractions like the Thomas Viaduct, the Patapsco Valley State Park, The Relay House was a 3-story, 32-room restaurant-inn-stables, built for the use of horse-drawn cars traveling between Baltimore and Ellicott's Mills (13 miles (21 km)); this was the first part built of what would become the Railroad's main line to Wheeling, Virginia (since 1863, West Virginia).
The engine misfunctioned and the horse won, but the viability of steam locomotives was successfully demonstrated.
In 1835 the Thomas Viaduct opened, providing the first rail service to Washington, D.C., and the use of horses was discontinued, although the station was still called Relay on railroad maps.
New platforms with benches and roofs were built along the tracks, but the Relay House was still close enough that trains could stop for meal breaks.
The names Relay and Relay House occur frequently in the reports on John Brown's raid on Harpers Ferry,[4][5] the last major event before the Civil War caused operations on the line to be shut down.