So what does any of this have to do with BART's use of a broad gauge. Assinine conspiracy theories and ridiculous comparisons to communist railroads aside; the fact is that by keeping maximum car width at the standard 10 foot 6 inches, while increasing the stance of the vehicle by some 17%, lateral stresses on the truck assembly was significantly reduced. Meaning that they could be made significantly lighter and that a significantly more stable ride could be provided. They whole industry would have been better off today, had the Erie gauge (6 ft) been adopted as the standard way back when; or even wider yet. But I digress.

It is also a fact that the first cars delivered to BART had the standard tapered wheels. And yes they did hunt, very mildly in my opinion. I put at least a thousand miles on them as a Q5 tester - so I ought to know. It certainly was no worse than any other passenger train I had previously ridden. Not only that, they were whisper quiet; with almost no flange noise or wheel slip noise (except when rounding a curve well below equalibrium speed). But somebody up the ladder obviously didn't like the ride, and summarily ordered it changed.

And this is where they went wrong. No experimentation with changing to a slimmer taper to match the much lighter weight of the car was ever done. Just "Do it" was the order of the day. Moreover, no oscillation damping was ever experimented with either. And since properly tuned damping is essential to a smooth ride and is critical to keeping the wheels firmly and safely on the rails; this was just the beginning of BART's troubles.

Actually, is was the just end of the beginning of their troubles - as there were other serious issues. The truck was by all other rail standards, way too rigid, with only two non-symmetrical hinge points, one on each side, and no snubbers, shock absorption, nor any other obvious damping means. And indeed, chronic wheel lift (a few thousandths) plagued the train control system, as well as causing rail corrugation.

But the penultimate disaster in this design, in my view, was that Bechtel failed to specify at all, how well the cars had to shunt the track - hence the car builder did whatever they wanted. Compounding this was that Bechtel specified a .06 track circuit sensitivity, when it should have been .25 sensitivity for such light cars.

It is true enough, the amplitude of the hunting was reduced to a minimal level; but only so long as both flange corners were tight against the rails at the same time. Which condition did not last very long before serious wear would compromise it. As this wear progressed, violent side to side slapping against the rails would occur when above equilibrium speed, especially in the rear car. It was not then uncommon to see passenger get up and change cars.

This excessive wear of both rail and wheel has plagued BART ever since, requiring premature rail replacements and wheel flanges dangerously worn before they get replaced. Indeed once the flanges get worn to a razors edge (it happened a lot), the wheels could and did climb up over worn rails, thus producing a rash of derailments. This rash of derailments was finally investigated by the NTSB, which faulted BART for its inability to keep up with maintenance requirements. But when you have to replace rails with only 5-7 million gross ton-miles on them, those requirements are onerous indeed; and with such light weight cars, are directly attributable to the exclusive use of cylindrical wheels.

But it doesn't stop there. As the British had earlier found out the hard way, some gentle hunting is critically necessary in maintaining a clean non-galvanic rail to wheel interface, so as to be able to reliably detect trains - Sort of necessary if you don't want to randomly kill your customers.

So yes, the obsessive desire to create a whole transit experience for the people, went awry. Not because of the gauge, which was a rational decision from a technical perspective (though not a strategically good idea); but only because they refused to to take into account the hard lessens of the past, and learn from other people's experience - building upon it. But they did learn that lesson later, adhering much more closely to industry standards more recently.



But hey - who are we to throw stones at an earlier generation about a blatantly foolish refusal to learn from other people's hard experience, when we are far worse than they