i have several pdf's of articled from Jan '62, Feb '62 and Mar '69
greg - Philadelphia & Reading / Reading
I recall building a TAT IV back in 1979. I don't remember which article (or series of articles) I used then.
This thread mentions the March 1969 issue as having the TAT IV article:
https://cs.trains.com/mrr/f/744/t/202840.aspx
I remember completing the throttle and testing it successfully but today I can not recall at all what I did with it
Perhaps I made the TAT V throttle. It seems that article was in the June 1975 M-R:
jjscott2The mystery of this throttle is now solved (mostly). The circuit matches that in the June 1975 article "Transistor Throttle With A Future". My throttle has two additions: a volt meter and an extra potentiometer. The pot is added to the momentum circuit at terminal 16. R7 is replaced with a 10k ohm resistor; the pot is 50k ohms.
(From the aforementioned thread)
If you really want to go back to origins I believe the first Linn Westcott article for a transistor throttle was the Feburary, 1962 issue. The "Blunt Brake" was an interesting concept addressed in the August 1968 issue.
Good Luck, Ed
Many years ago there was an article in MR on how to build a DC throttle. I built one and now can't find the article. I need to replace something on the PC board and need the article to work with. If you know what issue the DC throttle article was in, please respond with the issue date and page. Thanks. Capt. Brigg Franklin