Captain Underpants wrote, on 11.6.08, that: "There is a spur off the UP ... that goes into the BART South Hayward shop complex; once inside the fence, the track becomes dual gauge, with at least one dual-gauge switch."

I'd appreciate a photo of both, since I'm having trouble understanding how this might work. Here is why I'm puzzled: Dual gauge track "usually" has 3 rails, one a common rail and two others on the opposite side, one for each gauge. The distance from inside the common rail to the inside of the (UP) standard gauge rail is nominally 56.5", and that standard gauge rail itself is probably 3" wide, thus creating a distance of 59.5" from the inside of the common rail to the outside of the standard gauge rail on the other side. With the BART gauge of 60", that leaves only .5" for the flanges - and I don't think that works.

(Doing some other research years ago, on the railroad in Panama which was built to the "Russian" gauge of 5 feet, I found that one explanation given for the Russians having selected that gauge was to make it impossible for Germany's military to easily expand into Russia by laying a third rail on the Russian tracks to allow the German locomotives and rolling stock, apparently at that time built to the 4' 8.5" gauge, to operate.)

Just plain dual gauge track is hard enough to picture, and when I think of a dual gauge turnout my mind goes blank on just how the clearances could be handled.

So, I hope someone here who has actually seen this setup will describe it in more detail. Better yet, since it is apparently visible from the Capitol Corridor trains, could someone take a photo or two and post it.

Many thanks, and best regards to all.