The January 11 Bellevue Reporter headlines “Sound Transit to start probing along light rail line’’ is another example of ST incompetence. Any concerns they may have about installing light rail tracks along the route into Bellevue pale in comparison to those associated with light rail operation on the I-90 Bridge.
No one has ever attempted to install a train on a floating bridge. The concern is with the ability of the “expansion joints” connecting the “floating” and “fixed” portions to withstand the loads from the train’s four 74-ton cars. (The original bridge joints have already needed replacement under less severe loads.)
The Federal Highway Administration (FHWA) was sufficiently concerned they responded to the Draft Environmental Impact Statement on February 23, 2009 (HRW-WA/WA624). It concluded “We do not agree that enough work has been done to justify that it is feasible to design an expansion joint to accommodate light rail”. (The “work” they referred to was some 2005 tests the WSDOT had conducted using “flat-bed” trucks. See 7/04/12 post for more details)
Chapter 7 of the Final Environmental Impact Statement (FEIS) does mention these concerns: “The Federal Highway Administration’s (FHWA’s) concerns on the Draft EIS focused on the feasibility of light rail on the floating bridge and requested additional information on the feasibility of an expansion joint to accommodate light rail.“
Table 7-1, Common Comments, includes the following question and ST’s response
CC3n Can the I-90 floating bridge structure support the light rail?
The Washington State Legislature Joint Transportation Committee commissioned an independent review team (IRT) to evaluate the bridge design with light rail. The IRT concluded that all issues identified as potentially affecting feasibility can be addressed.
It’s “interesting” that ST chose to refer to a study commissioned by the legislature rather than conduct further studies in the intervening 2 ½ years. The fact the independent study concluded “all the issues identified can be addressed” surely suggests more needs to be done.
As the 7/04 post points out future studies may conclude that structural concerns could limit each train to only 2 cars; halving East Link’s already meager capacity. The fact ST still refuses to do those studies nearly 4 years after the FHWA raised concerns is just another example of their incompetence.