The B&O Railroad first built a trestle over the Rock Creek stream valley in 1892. The first trestle was a 1400' long wood structure. The trestle has been rebuilt several times over the years, and most of the original wood structure has been replaced by earth fill. A 281' long, 67' high span remained above Rock Creek when railroad service stopped on the Georgetown Branch line in 1985. The trestle was damaged by arson and was closed as unsafe.
In 1988 Montgomery County purchased the Georgetown Branch right-of-way, including the trestle, for use as a future trail and transit line. In 1996 the rails and ties were removed and an "interim" crushed stone trail was built to give the public some use of the right-of-way while planning continued for the future transit/trail project. Trail users had to follow a hilly and circuitous detour of the closed trestle to cross the Rock Creek stream valley, and few people used the section of the trail east of Rock Creek. In June 2000, following strong advocacy by the Coalition for the Capital Crescent Trail (CCCT), Montgomery County committed 1.3M$ to repair the trestle and open it for trail use.
The trestle was repaired in a manner that retained much of the old trestle structure. Prefabricated bridge spans were placed over the top of the old trestle, and are supported by the old steel substructure. Use of prefabricated bridge spans minimized construction impacts on Rock Creek. The prefabricated spans can be moved and used for trail bridges elsewhere if the trestle must be removed to make room for a new transit/trail bridge.
At 12' wide, the bridge deck does not have the minimum 14' width recommended by AASHTO national guidelines, and is not as wide as the other trail bridges on the CCT. Unsafe and unpleasant conflicts would arise between trail users stopping to take in the view and those not wishing to stop if there were no provision for trail users to stop on the trestle. An observation deck was added to the project. Three civic organizations (the CCCT, the Greater Bethesda-Chevy Chase Coalition, and the Washington Area Bicyclist Association) contributed 2/3 of the additional cost of the observation deck, with Montgomery County contributing the balance. The observation deck is 30' long and 22' wide, and is directly above Rock Creek at the trestle mid-span. It provides a safe place for trail users to pull over and enjoy the views from the trestle without standing in the flow of trail traffic.
The trestle was dedicated for trail use on May 31, 2003. The trestle now gives the Interim CCT (a.k.a. Georgetown Branch Trail) a direct and level crossing of the stream valley, and offers spectacular views from high above Rock Creek Park.
See the trestle rehabilitation in progress at trestle archive.