Operating Era: 1943-1973. THIS SERIES NOW COMES WITH OUR ONE-PIECE ROOF FRAME. Atchison, Topeka & Santa Fe. After the successful coversion program of the Sk-2 (see kit 7601), Santa Fe converted another 1,121 Bx-3 and -6 box cars (see kit series 3600) to class Sk-3 stock cars. The conversions differed significantly, however. Radial roofs salvaged from Bx-8, -9, and -10 box cars were used rather than the original equipment peaked, plain mullion roofs. This required cutting the peaks off the ends. The slatted doors used wider X-bracing. Top door rollers replaced door guides and bottom rods replaced door rollers. The cars ran as converted well into the 1970's, the last cars being listed in the ORER in 1974. PLEASE SEE OUR DS BOX CAR, REFRIGERATOR CAR AND MOW & CABOOSE SECTIONS FOR OTHER AT&SF Bx-3/6 TYPE KITS IN OUR #3600, #3700 SERIES.