i'm an electric model railroader (HO gauge) working on an electronic controller having both a reverser lever with multiple notches for cutoff and a throttle that will more accurately emulate steam locomotive behavior. It should require the operator to properly use the throttle and reverser to gain speed without depleting the boiler of steam. (i'm an EE retired from Bell Labs and Qualcomm)
the attachment plot from a simulation shows speed (blue), boiler pressure (white), cutoff (orange)
the software model assumes saturated steam where temperature, pressure and density are directly related. Use rpm and cylinder volume to determine steam consumption (lbs) and equal amount of water to replenish in boiler and determine resulting temperature/pressure. The plot shows the decrease in steam pressure with speed and its recovery with the reduction (% valve open) of cutoff
looking for help to verify my understanding and calculations for drawbar force, max TE and condition for slipping. In particular an understanding of how the throttle affects cylinder pressure.
dealing with a more accurate model based on super-heated steam, pressure drop thru steam pipe and back pressure thru exhaust remain beyond my understanding but may be unnecessary.
using the following parameters (and a gross estimate of boiler water capacity) for a few Reading locomotives and an Australian locomotive
Code: Select all
# DrvrDia CylDim PSI Wt Grate BlrLen BlrDia Desc # in inXin ton sq.ft ft in locoDesc 61.5 27 32 220 132 95 13.5 88 I-10sa locoDesc 80 25 28 200 150 95 19.00 80 G-1sas locoDesc 61.5 30.5 32 220 200 108 22.25 100 K-1 locoDesc 70 27 32 240 200 95 13.50 88 T-1 locoDesc 36 13 18 180 13 9 11 40 NA_2-6-2
greg - somerset, NJ