The design of freight locomotives for U.S. railroads began changing in late-1990 with the introduction of the first industry crashworthiness standard for the front nose of newly-manufactured freight. Between 1990 and 2008, that industry standard was revised and upgraded four times. In 1995 an industry standard for the crashworthiness of fuel tanks mounted underneath newly-manufactured freight locomotives was also introduced. Effective at the end of 2008, both of the industry standards were incorporated by reference into a new U.S. federal regulation mandating crashworthiness features on newly-manufactured locomotives effective with deliveries to railroads in 2009.
In addition to the crashworthiness-specific design changes, in 1992 and 1993 both of the major U.S. locomotive manufacturers introduced new designs for the attachment of the truck (bogie) assemblies to locomotive underframes; these changes were to facilitate the use of new trucks (bogies) producing higher adhesion for greater tractive effort. The “deep traction pin” designs also had a positive effect on the crashworthiness of new fuel tanks by reducing the chance of truck separation from the underframe (and impacting the fuel tank) during accidents. The changes cited here were for newly-manufactured freight locomotives, with retrofit to older locomotives impossible or extremely difficult to accomplish with similar results.
This paper briefly reviews the introduction of the crashworthiness features described, and also offers the first retrospective look at (a) how extensively the evolving crashworthiness features have reached across the U.S. freight locomotive fleet (through acquisition of newly-manufactured freight locomotives) and (b) attempts to measure the effectiveness of the various crashworthiness design changes in saving lives and reducing injuries of in-cab railroad employees.
It is believed that this paper is the first and only assessment to date of cumulative U.S. freight locomotive crashworthiness progress and its statistical impact on locomotive crew safety since the early 2000’s.