If you will read contemporary trade journals you will find that many BART design features were the result of extensive research by competent engineers. They were not being different just for the sake of difference. For example, wind tunnel tests revealed a wider track gauge would give a smoother ride on elevated track structures in prevailing Bay Area winds. Each experimental increase improved ride up to about 5' 6". Beyond that width produced little improvement. So they decided that gauge would be cost effective. Since BART never intended to exchange cars with other railroads, incompatibility was no problem.

Other than things like track spikes, almost every thing for railroads is built to order. Almost nothing comes off the shelf. The additional steel used for wider gauge equipment was only a minute part of the cost.

The BART wheel contour was the result of experiments performed in house by the BART engineering staff; they cured truck hunting problems. So statements blaming Bechtel are more ignorant railfan babble. Unfortunately a lot of wrong information keeps being repeated. A lot of self- appointed experts and conspiracy theorists sound off.