What is the GP9-4? can you maybe explain to me who rebuilt the GP9-4, when they rebuilt it and what was the purpose of the GP9-4?
Did RLK rebuild them in 1996? 1997? or 1998?
From what I found so far, RLK rebuilt five GP9-4 locomotives from five former Southern Pacific GP9E/GP9R locomotives. That’s all I found so far, as there is no information about the GP9-4. Which to me it feels like a GP9 locomotive that is underrated.
The -4 is a designation made by the rebuilder, and is used (by them) to identify the changes/updates they made when they rebuilt it such as engine upgrades, improved electronics, autostart units, etc.
The original use of this was to designate the very important set of changes made by EMD in the ‘dash-2’ line of improved locomotives. It was very significant as such.
Railroads cunningly leaped on the ‘two legs good - four legs better’ analogy with various kinds of ‘dash-3’ things, obviously from the name more ‘advanced’ in some more-or-less-inchoate fashion from the locomotives being modified.
What could be more logical for Republic, in the heady Starship years, to leapfrog the competition with a yet-more-advanced dash-4? Somewhere there are probably marketing materials touting the improvements, and I’d like to see them.
The problem, as with the GP15 whatever its suffixes were, is that there was comparatively little demand for an expensive rebuild of a GP9 into an improved GP9-size locomotive. The CF7 program worked because of all the costed-down F units; the Paducah-style rebuilds worked because of all the costed-down Geeps at IC and elsewhere… and the comparative cheapness of the common-sense changes made. Note in particular that something I thought was a no-brainer, the E10 rebuilding for Amtrak, was ‘not proceeded with’ (I guess related to the SDP40F procurement). And I’ll bet a hat there are still many who bewail spending All That Money on the Starships – delightful as they were to read about and behold!
I don’t know of any use of a dash-number system on early Geeps that followed the EMD scheme. Many of them used a letter – GP9E, GP9M, GP9U, etc. (the letter meaning “what the railroad wanted it to mean”) or changed the number to reflect a supposedly- improved version: GP8, GP10, GP11.
You presently see widespread use of the dash-3 to indicate various modified versions of EMD second-generation and sometimes newer locomotives. I think you’re supposed to assume ‘dash-2 was good, so dash-3 is better’ even though in many cases the dash-3s are deturboed or otherwise modified for lower horsepower.