Originally constructed in 1963, the J. P. Morgan Chase Tower Complex consists of a high-rise office building containing approximately 351,200 square feet of gross building area in a 19-story tower building with a five-story parking garage. In addition, at the lowest below-street level of the building there is a tunnel containing a main line three-track railroad roadbed that bisects the site. The tracks were in-place before construction of the building. The site drawings received indicate that vibration isolation was considered during design and construction. The garage and basement portions of the facility consist of steel columns and beams supporting a reinforced concrete pan joist floor system. On the lower levels, the steel framing is encased with concrete for additional strength and fireproofing. Reinforced concrete walls surround the below grade parking and building spaces and form the tunnel walls. Some interior walls, such as the elevator walls below street level, are masonry. The upper levels contain office and retail spaces, and consist of structural steel framing and concrete composite floors. The exterior skin is a combination of materials including aggregate surfaced concrete panels, stucco over brick, Mexican onyx, Spandrelite, and glass curtain walls. There are glass curtain walls along the ground floor. Terracon was retained to provide a limited structural survey and review to investigate possible structural problems that may arise due to vibrations from the underground railroad traffic. To accomplish this task Terracon used triaxial geophones, linear microphones, and data storage units to monitor and record vibrations during train activity. The instruments were placed on various building levels and initially recorded events in a continuous mode. Histogram logs of event data were then recorded over a six-day period. The vibrations recorded were reported as Peak Particle Velocities and frequencies for each ordinate direction. The results of the test program were compared to both U.S. and European standards. In each instance it was shown that the vibrations and frequencies measured were well within the published guidelines.