High or Low? This guy has several of these, some interesting, some....?

I'll go with Urban Transit Systems and Technology, by Professor Vukan Vuchic, where you look at number of cars in a train, number of doors, number of on-offs, ADA access/loading times, overall dwell times/train movements per hour, etc.. His engineering/design/operational analysis oriented texts are also big on table with emperical findings and comparisons of various transit systems with different volumes, on-offs, and other data, to give you a range of the various cost/benefit/operation tradeoffs on details like these.

Back when we were looking at this back in the 80's high level LRT platforms made more sense for LA, with high expected on-off volumes (remember the Blueline has three time for passenger density per mile than the BART system has) and still had to be retrofitted expanded to three car trains and platform extensions, which were designed into the Goldline based on that experience being gained). When the LRT system was first planned in LA, folks wrestled with this, and took some heat for that high level platform choice back then, as other cities (Sacramento/San Diego, others) had gone for more of a "streetcar" low floor LRT platform (Sacramento, with the innovative ADA ramps). The other costly idea is the variable Muni height platform system (first on the Boeings), extra costs, extra maintenance headaches, but necessary because of the existing low platform feeder lines into the new Muni market subway, where the on-off volumes are very high.

Many who chose low level platforms ended up with problems, which created loading problems and delays (especially as system on-offs grew, and problems with ramps and ADA compliance became a bigger issue), This has created more demand for "low floor" rail vehicles (not a new concept) vehicles, that had the easier "cross platform" advantages of high level platform stations/stops for faster loading and easier ADA compliance, without the higher construction costs. Low floor buses are another variation on this ease of loading concept, although often poorly executed in the US.