Helpers - For Radius Leaf Type Springs
S - Series - 1000 through 8000 series, Amtran and IC - Rear Single Axle - Helpers
S - Series (1978-88)
1400 through 1652 (1987-2012)
2554 through 2674 (1989-2002)
3000 - 3400 through 3900 (1989-2004)
4500 through 4900 (1989-2003)
7100 - 8100 through 8300 (1988-2003)
Amtran Genesis, Amtran FE and RE; IC CE, FE and RE (To 2004)