By the way, what is the legal jam on converting the line to light rail? I'm reading that there's something that limits service on the line to either BRT or a deep bore subway.
I recalled that it was mainly San Fernando Valley residents' opposition to any rail option that wasn't a subway that resulted in the BRT Orange Line, but this Wikipedia entry, if accurate, gives a more complete picture of the history:Orange Line (Los Angeles Metro)
"At the time, then-L.A. Mayor Richard Riordan had suggested some type of 'trench' construction in which to lay the rails to save money and extend the subway trains to Warner Center: 'Some way to get it out of the ground,' Riordan said, referring to a trench's much lower cost to construct compared to deep-burrow tunnel boring machines (TBM), and to address the objections of residents for any elevated line. However, local community groups fiercely opposed such alternatives and, in fact, any rail construction that was not completely underground."
Legislation prohibiting rail was enacted:
"Prior to his 1993 conviction and prison sentence for accepting bribes, California state Senator Alan Robbins introduced a piece of legislation which prohibited the use of the corridor for any form of rail transit other than a "deep bore subway
located at least 25 feet below ground." The California Legislature passed it as law in 1991."
On capacities, BRT vs. light and other rail, I once read a fairly detailed treatise online that gave numbers, but I'll be damned if I can find it. This Seattle Transit Blog piece (2008) includes some capacity discussion, and the website might provide a starting point for a better search than I've been able to do...Why BRT Doesn't Make Sense
"Some BRT advocates will tell you that buses can have exactly the same capacity as rail. They're either uninformed, or they're lying. Even with double-articulated coaches as in Curitiba [Brazil, often cited as the model for BRT], you're looking at an 85 foot long vehicle with 57 seats. Curitiba claims they can reach 270 passengers – but at the measure of 6 passengers per square meter standing. With half that standing density, 3 passengers per square meter, our light rail cars carry 200 (with 74 seated). If you went by Curitiba standards, we'd carry more than 325 people per car. These cost about the same amount to operate and maintain – for the sake of discussion, about half the operations cost of a vehicle like this is the fuel, and about half the operator, although that now varies a lot more with the high cost of fuel prices, so my comparison gives buses a slight advantage.
"But wait – we can tack three more vehicles onto a Link train behind the same operator. If we want to add another bus, that means paying another operator, so Link scales to four car trains at some 5/8 the cost – and a full metro can go much higher, with as many as 12 cars. We can also go down to lower headways than the buses can without affecting service quality – the big limiter is the time taken to board, which is a lot lower for four simultaneous light rail cars than four sequential buses, even when the buses have multiple doors. Rail can also offer a very finely tuned interface between vehicle and platform – on new systems, no ramps or lifts are necessary for wheelchair users."
For a non-capacity (in strict terms) comparison of BRT vs. rail there's this grid of other stats, also from Seattle Transit Blog: