Designed for optimum speeds at the head of the roads crack passenger trains, the J was tested at speeds of 115mph,but the engineer closed the throttle out of concern for safety. These well-liked locos lasted in service into the late 1950s. One notable surviving J, #611, was the star on excursion trains into the early 1990s.
 
These DCC-ready locomotives feature all-new tooling, operating headlight, separately applied metal parts, alligator cross heads, a see-through frame, RP25 wheels and E-Z mate(R) Mark II couplers.