Hi, I'm trying to understand (and write a very simple simulator) for train brake systems. I've worked with similar systems in the past (not mainline -- rapid-transit-type systems, which are similar, but not quite the same). Anyway, I think that if I model types 6BL, 24RL and 26L, I'll have the gamut of typical systems covered; at least anything you're likely to see in diesels. I'm looking for technical data on these systems -- I can find operating manuals, etc for these systems, but I can't easily find some data that I'm looking for, nor some operating facets: a) First, making sure I'm correct: the major difference between the 6BL and 24RL systems was that the 24RL systems use an equalizing reservoir and feed valve (i.e. the "maintaining feature", while in the 6BL system the handle basically connects the brake pipe either to main reservoir or atmosphere directly? b) For the 24RL system, then, It should be pretty straightforward to measure the rate (in Psi/sec) at which pressure changes in the EQ Reservoir vs each handle position? (i.e. you get something like 2.5Psi/sec reduction in service, and 4.5 Psi/sec charge in appy?) Does anyone know where I could find this information? c) In all of these systems, is there something that prevents the engineer from making an over-reduction: i.e. if you have a 90Psi brake pipe, once you make a 25psi reduction, that's full service (for a 2.5x ratio system); if the engineer keeps a 24RL handle in "service", does the brake pipe get reduced lower than 65psi? What does the brake pipe go to in full service on a 26L? Generally, I'm guessing there's brake service manuals that would have this kind of information, as it's all stuff you'd want to test if you were servicing the systems; I just can't seem to find service manuals like this online.. Any tips (or even direct answers to some of my current questions) would be appreciated..