I scanned through the Standard Catalog of Prewar, and came up with four sets that the #38 headed. The #38 was available from 1913-1924, and the sets were numbered Set 39-- 38 loco, 116 Ballast, 117 Caboose
Set 40-- 38 loco, 35 Pullman, 35 Pullman, 36 Observation
Set 41-- 38 loco, 112 Gondola, 113 Cattle Car, 114 Boxcar, 117 Caboose
set 45-- 38 loco, 31 Combine, 32 Mail, 35 Pullman, 36 Observation