The platforms contain I-beam columns spaced every . Additional columns between the tracks, spaced every , support the jack-arched concrete station roofs. There is a gap between the trough wall and the platform walls, which are made of -thick brick covered over by a tiled finish. The walls near the tracks do not have any identifying motifs with the station's name, as all station identification signs are on the platforms. The trackside walls contain vertical white glass tiles. The original decorative scheme for the side platforms consisted of blue tile station-name tablets, blue and buff tile bands, a yellow faience cornice, and blue faience plaques. The mosaic tiles at all original IRT stations were manufactured by the American Encaustic Tile Company, which subcontracted the installations at each station. The decorative work was performed by faience contractor Grueby Faience Company. Track layout Similar to 72nd Street on the IRT Broadway–Seventh Avenue Line, this station was built with extra tracks on the approach to the station. These were between the local and express tracks and were approximately long. The idea was to have a "stacking" track where a train could be held momentarily until the platform cleared for it to enter the station. The tracks here and at 72nd Street were rendered useless when train lengths grew beyond these tracks' capacity. The northern track was removed as a result of the 1991 derailment. A similar track still exists between the northbound tracks south of the 14th Street–Union Square station's northbound platform. BMT Broadway Line platforms The 14th Street–Union Square station is an express station on the BMT Broadway Line that has four tracks and two island platforms. The N and Q trains stop here at all times. The R stops here at all times except late nights, while the W stops here during weekdays. The island platforms were originally long, but as a result of an extension in the early 1970s, became long. The platforms are below the street. At the southern end of each platform, three stairs and an elevator lead to the mezzanine, and one stair leads to the Canarsie Line platforms. At the northern end of each platform, two stairs lead to the mezzanine. The tunnel is covered by a "U"-shaped trough that contains utility pipes and wires. The bottom of this trough contains a concrete foundation no less than thick. Each platform consists of concrete slabs, beneath which