Does anyone know why they only built the Alameda Corridor to 40mph speed limits? Looking at the Corridor on a map, it looks like it contains mostly straight stretches with a few small bends (so steep curves shouldn't be a problem). It's long enough, too, to benefit from higher speeds--if it were only a few miles long, I could understand that it would be pointless to have trains accelerate to 70-75 mph for just a couple of minutes. Higher speeds would also increase the capacity of the Corridor, and while saturation isn't expected until probably 2025, it's usually cheaper to build for the future (especially with new construction) than it is to rebuild it later.

Most of the infrastructure for higher speeds is already in place on the Corridor--shallow curves, long straight stretches, grade separation--the only things I see that limit speeds are track weight and FRA-mandated tolerances for gauge, and that shouldn't have been that much more expensive on new construction.

Even if the need isn't there now--there's probably not a huge rush to get from the harbor to the downtown railyards (I don't know if all Alameda Corridor traffic is strictly between these two points or if some trains continue directly onto the transcontinental mainlines--if it's not that much more expensive to build it to higher specifications, why didn't they? The only thing I can think of is a political reason: noise pollution of roaring engines leaking out into nearby neighborhoods.

Perhaps possible speeds will increase with the proposed electrification project...