Seattle Monorail

System Description

Seattle Center Monorail system is composed of two trains and a fixed guideway.  Each train runs on its own dedicated “rail,” which is composed of 68 y-shaped columns supporting pairs of concrete beams, which span the columns.  The typical pre-stressed concrete beams are approximately 70ft long.  The highest columns are around 30ft overhead.  The guideway is just under 1 mile in length at the present day, but when it was built in 1962, it extended beyond Westlake Center and was a little longer than 1 mile.  Construction of the guideway began in April 1961 and was completed in January 1962.

There are two trains: Blue Train and Red Train.   The trains were built by ALWEG Rapid Transit Company in West Germany in 1961, and were shipped to New York City where they were placed on traditional rail cars and transported to Seattle.  Blue Train arrived before Red Train, and was placed on the beam in February 1962.  On March 3, 1962, Blue Train made its first test run.

Each train has 64  tires: 16 load-carrying tires ride on top of the beam, and 48 guide tires run along the sides of the beam for alignment purposes.  The 16 load tires run as duals in eight wheel/suspension assemblies called “bogies.”  Each bogie has 2 load tires, 6 guide tires, an air suspension system, a 700VDC motor, gearbox and drive train, and a brake assembly.  The motors were manufactured by GE and the gear boxes were built by Rockwell.

The  Monorail trains run on 700 volts DC, which is supplied to the trains through contact rails on each beam.  Carbon shoes contact the copper-headed rail to transfer power to the propulsion system, which in turn supplies current to the DC motors.

In 2008, a major refurbishment project started with the bulk of the refurbishment work being completed in 2011, although there continue to be ongoing projects.  During this refurbishment, all of the bogies were overhauled, and the low voltage electrical and pneumatic systems were completely replaced.  In addition, the power rail and insulators along the 1-mile guideway were replaced.  This work was very necessary after nearly 50 years of operation.  The refurbishment work was very successful and resulted in improved reliability and serviceability.