Figure 5.2. Open-Floor Bridges.
Track over ballasted-deck bridges is surfaced and lined by tamping and with lining bars--the conventional
methods. With open-floor bridges, such work is more difficult because there is no ballast to simplify moving the
track either vertically or horizontally. The work must be done by shimming, changing tie size, notching, or
elevating. Each tie must be custom made for its individual location.