The Mousehole

SR 89 Mousehole UPRR Undercrossing Improvement Project

 In 1928, the SR 89 Union Pacific Railroad (UPRR) underpass was constructed under a temporary timber-supported trestle. Although the narrow section of roadway was once acceptable, much has changed in the past 80 years which has rendered the undercrossing inadequate. Traffic volumes through the area have increased and the Mousehole provides a point of constriction along SR 89 which can cause bottlenecking on peak traffic days, impairs emergency vehicle access. Along with increases in traffic, increases in pedestrian and bicycle activity through the Mousehole have occurred. Due to lack of shoulders through the Mousehole and the high pedestrian activity, a deficient pedestrian and bicycle environment has developed.  Finally, the current Mousehole does not provide adequate vertical clearance to allow passage of all trucks.

For these reasons, the Town of Truckee, Nevada County Transportation Commission, and the California Department of Transportation are working together on the SR 89 Mousehole UPRR Undercrossing Improvement Project. The purpose of the Mousehole replacement project is as follows: 

•  Improve mobility.

• Improve traffic operations with particular attention to reducing the bicycle//pedestrian/vehicle conflicts at the grade separation.

•  Use the highway facilities as efficiently as possible.

• Rehabilitate/overlay SR 89 on both sides of the railroad grade separation to the intersections at Deerfield Drive to the north and West River Street to the south.

Mousehole Fact Sheet

Several alternatives have been reviewed to date, including the construction of a new bridge in place of the existing Mousehole structure, a new bridge on a realigned railroad alignment, and new tunnel structure(s). Below are some alternatives that have been reviewed in the past and presented in a public workshop in September 2006.

• Alternative 1 - Bore a single new tunnel for pedestrians and bikes only

• Alternative 2 - Bore a single new tunnel for two traffic lanes, pedestrians
  and bikes.
• Alternative 3 - Bore a new tunnel for two lanes of traffic and a new
  tunnel for pedestrians and bikes.
• Alternative 4 - Construct a bridge with four lanes of traffic, and no
  median.
• Alternative 5 - Construct a bridge with four lanes of traffic and a median.

Caltrans is currently working on the Project Approval and Environmental Document (PAED), which is expected to be complete in 2009. For more information, please contact Becky Bucar, Assistant Engineer at bbucar@townoftruckee.com or (530) 582-2932.