What was the greatest amount of diesel manufactures in a single year ?

I think you need to narrow your question.  This is very difficult to answer because there were many small companies over the years that made diesels in addition to the big two - EMD and GE.  GE got into the business late and then overtook EMD.  Some railroads built their own diesels.  

Then you need to consider non-USA companies because this forum has an international following.  England, Germany, Russia, China, France, Australia, etc.  

There are more companies making diesels today than you might imagine.  There are probably at least four or five companies in the USA alone today.

Joe  

Another thing to consider is the ever increasing HP of diesel locomotives.  One of today's locomotives might have three times the HP of a 1950s diesel locomotive. If you go to the Railway Age magazine web site and then goto the Management News section, there is an article with the statistics from the AAR on locomotive deliveries for the last ten years. It gives you an idea of what is going on.  Considering that the railroads are moving more ton miles of freight today than ever before, and they are moving it faster, there is probably a record amount of HP and/or TE out there right now. 

  I guess I should have stated those built by American companies.

  I sorta figured this would bring up a few questions,because it took me a few minutes and second guesses to figure out how to ask the question with out being to lengthy .

  I'm guessing the most made might have been in the 50's or 60's.

 But I am mainly referring to those built by companies other than railroads.

 I didn't realize any railroad built a "new model" on their own

I don't know how you can confirm it.

I would venture a guess that the time when steam was fading and diesels where being used (late 30's to late 50's)there was competition for new market. Some steam manufacturers tried to change to survive, but didn't make it. New ones tried to start and didn't make it.

American Rails gives one a start on the builders' history for the U.S.

I would take a stab at the SD40-2, which totaled over 3900 locomotives, admittedly over a 14 year period.

It would take a lot of research to nail down one specific locomotive model over the course of one year as production of various models could range from months to years.  

Plus, none of the major builders (EMD, Alco, FM, Baldwin, GE) built just one model at a given time.  They could have several types of locomotives going up side-by-side on the production floor.

Rusty

IC, CR, NS, ATSF, SP have/had large building/rebuilding plants(s).  Even tiny Tex-Mex rebuilt some of their first diesels at their shops in Laredo TX!

Another variable to consider is that the same locomotive model can be assembled by the locomotive manufacturer at different facilities in different countries. For example EMD used to assemble SD70ACe at the London, Ontario facility in Canada but now assembles SD70ACe at their US facility in Muncie, IN & also at the facility owned by Bombardier Transportation in Ciudad Sahagun, Mexico. The locomotive you see on a US Class 1 freight railroad might not be built at a US facility. EMD also builds locomotives like the SD70ACe & SD80ACe at a new facility they built in Sete Lagoas, Minas Gerias, in Brazil.

I recently read in some magazine that GE used to build all their locomotives for US freight railroads at the Erie, PA facility but has been moving the locomotive assembly to a new facility in Fort Worth, TX. Starting Jan 1, 2015 all their new locomotives for US customers would only be built at their Fort Worth facility.

These are just my opinion.

Thanks,

Naveen Rajan

Did that and thanks - good article. 

Hello mackb4

I would say its the F-3, F-7 and F-9 units made by many model train companies. I hope this answer your question.

The woman who loves the S.F.5011,2678,2003

Tiffany

I don't think so. Since this is the REAL TRAINS FORUM, he is asking about REAL DIESEL LOCOMOTIVE production.

And NS can build EMD's from kits!

 But remember,new from a manufacture not a railroad...and that was pretty funny Tiffany

If the question is what is the greatest number of manufacturers of diesel-electric locomotives active in the Untied States in any one year I would suggest looking to 1950.  In that year you had the following all building switchers and road locomotives.

Alco-GE

Baldwin-Westinghouse

The Electro-Motive Division of General Motors

Fairbanks-Morse

Lima-Hamilton

GE built switchers on their own too and GE built electric locomotives at their large facility in Erie, PA.  GE had just completed assembling locomotives at Erie for F-M.

In Canada there were three builders active in 1950.

The Canadian Locomotive Company built Baldwin and F-M designed locomotives.

General Motors Diesel opened their plant at London, Ontario that year.

The Montreal Locomotive Works was building Alco designed locomotives.