i keep finding lists of locomotives planned but never built on trains magazine
locomotives like the RB3600 , FG9 and ALCO C636P (pictured below )
i also found these MK5500AC , and MK6000AC and here is proof that these being planned
In the early 1990s MK Rail, a long time locomotive remanufacturer, announced its plan to compete directly with Electro Motive Division (EMD) and GE Transportation Systems (GE) by beginning its own high-horsepower locomotive program, starting with a 5,000 hp (3.7 MW) DC drive locomotive and continuing with 5,500 hp (4.1 MW) and 6,000 hp (4.5 MW) AC drive locomotives in later years.
what about GE's AC7100 or AC6800
Regarding the AC7100CW; General Electric did build a prototype 18 cylinder version of the HDL engine and there was discussion of it's potential use in locomtives. The actual model probably would have been an "AC6800CW" as the 7,000 rating was BHP....
For some reason i think the AC7100 would have been a cowled unit 
as for the RB3600 read this under double diesels
https://books.google.com/books...20rb3600&f=false
i want to build all of these
does any one know where i can find the catalogs of these engines if there are any schematic drawings i can go by
