I have been able to determine most of the 50 ton end-cab narrow gauge untis built primarily due to the contributions of P.A. Copeland, Steve Palmano, Joe Dale Morris, Jay Reed, and many others.
The first three built in August of 1952 were for the Chiriqui Land Co. (United Fruit aka Chiquita) in Panama. Right after the first three, two more units for the Granada Co. (another United Fruit?) in the Dominican Republic, they worked two railroads in Costa Rica before ending up in Panama. The first one built still exists, but it and the fourth one built might be scrapped any time now.
SP #1 was possibly the fifth or sixth order, about the eleventh built. I know there were at leat 13 other orders besides SP #1 for 36" gauge units, their might be more 36" gauge units beyond the last one built in July of 1957; and their might be more units built for other than 36". (Right now, Sumpter Valley has the next to last known one built). The majority of the orders were for 36" gauge units, but largest quantity were for 42" gauge.
Presently known buyers or this model, original known 36" gauge buyers were:
Chiriqui Land Co. (United Fruit Co. aka Chiquita) both Northern (Bocas Fruit Co.) and Southern divisions (Puerto Armuelles Fruit Co.).
Grenada Co. (Dominican Republic) (United Fruit?)
Cuban-American Sugar Co. for Central Chappara (Cuba)
Surinaamache Bauxite Maatschappji (Dutch Guiana)
Southern Pacific
IRCA (consecutive orders for Guatemala and El Salvador)
Standard Fruit and Steamship (Honduras)
Cuban-American Mercantile Co. (Cuba)(for Central Chappara?)
Maritrop trading Co. (see United Fruit Co. units)
Presently known buyers or this model, original known 42" gauge buyers were:
Northern RR of Costa Rica (last two orders have mu and dynamics)
Nac. de Venezuela for FC Puerto Caballo (listed as 1.070m gauge, now std, gauged?)
Manila RR (Philippines)
Presently known second or later owners:
FC del Quepo (Costa Rica)(former Granada Co. units, second owner 42")
FC del Sur (Costa Rica)(former Granada Co. units, third owner 42")
Chiriqui Land Co. (United Fruit Co. aka Chiquita) Northern div. (Bocas Fruit Co.)(former Granada Co. units, fourth owner 36")
Compania Minera de Cananea (Mexico)(SP #1)
Bandegua (Gautemala)(former Chirirqui Land Co. units, another UFCo. subsidiary at the time?)
Sumpter Valley RR and a private owner (former Chiriqui Land Co aka Bocas Fruit Co.)
A total of 59 known units built so far with one known 36" gauge order still unaccounted for.
