What did modelers in the 50s thru the 70s use for throttles?

I just used my old HO power pack.

I have a few catalogs from that era that were 2 rail DC oriented.  Let me go back and look.  The Marnold transformers were pretty common, but dedicated DC transformers go back to the early days of 2 rail DC operation in the 1930s.  None of the names come to mind for me at the moment unfortunately.

Most of the guys in our 1970’s era Washington  DC area O scale group custom built their own DC power supplies using high current transformers, rectifiers, and rheostats.  For walk around control I followed the lead of John Armstrong by using motor driven variable transformers, rectifers, and polarity flipping relays controlled by facia mounted push buttons (fast, slow, forward, reverse).  The 4  button pads , multiples for each power supply, were mounted around the aisles so the engineers could follow and control their train.  For multi- train operation the layout was divided into power blocks with rotary selector switches to associate each block with one of the 7 DC power supplies I was using at the time.  In the late 1980’s the variable transformers began to be supplanted by radio control DC power packs offered by Aristo, largely to the garden railroad community.    By the late 1990’s four amp DCC decoders came on the market,  and when combined with radio DCC throttles provide walk around control without then need for complex  block wiring.  Today’s O scalers now have additional options including blue tooth DCC decoders that can be matched with a variety of power on the rails, or on-board battery power.

I had some Marn-o-Stats from Walthers in the 1960s, but they were simply large-diameter half-circle rheostats with the long handles you mentioned. They were not very sophisticated and required an independent source of DC power, which often could be a car battery in the 1930s and 1940s, to judge from old issues of Model Railroader. There was no momentum setting or anything like that, of course.

Some people experimented with autotransformers -- designed for industrial use -- that allowed direct adjustment of voltage output (AC) through a large knob on the device. They were potentially dangerous because of the way the primary and secondary windings were combined. Someone with more knowledge of electronics than I have will be able to explain them better. I purchased an autotransformer at one time in the late 1960s, but did not end of using it because of warnings against possible electrocution and damaging over-voltage on the layout.

Later on, nicely packaged control centers designed for 2-rail DC operation came along, with transformer, solid-state speed control and braking/momentum capabilities all contained within an attractive box. GML was one later provider of simple, dependable solid-state DC controls with integrated solid-state rectification of the AC input from a separate transformer that were designed to be mounted on the layout fascia, with or without a tethered throttle. I have been operating my 2-Rail layout with a basic GML throttle for over 20 years without any problems. The maker has gone out of business, unfortunately.

@Keystoned Ed posted:

Most of the guys in our 1970’s era Washington  DC area O scale group custom built their own DC power supplies using high current transformers, rectifiers, and rheostats.

My FiL built 2 DC power supplies just like what Ed describes for me - still using the one attached to the layout; 2nd one is in reserve. Got an old (?) HO power supply that I use at the bench for testing everything.  If I wanted more than that, and I don't, then I'd bother with "upgrading".

i wish MRC did a nice copper colored 2.5 to 4.5ish amp single throttle, if it had meters it would be even better.  I know my old HO golden throttle pack does not like running All Nation open frame motors in the F3's for very long.   It will do it but gets hot quickly.  I always loved the looks of the copper colored metal case MRC packs, but they are pretty much designed for the HO and N crowd.  Or low amp draw can motor O scale.   I have no interest in putting dcc in right now.  I do have a NCE PowerCab system.  Would need a higher amp transformer than the wall wart job it comes with for O scale power demands.   

Gilbert introduced DC versions of their 332 4-8-4 Northern and 342 0-8-0 switcher in 1947. Gilbert cataloged a 150W "Directronic Rectiformer" to operate these trains. It used a vacuum tube as the rectifier. It was priced at $25. They also cataloged a 4A selenium disc rectifier mounted on a chassis with a DPDT switch so an existing AC transformer could be used. These cost $12.95. Gilbert sold a lot of S gauge American Flyer DC engines from 1947 through 1950 along with the DC Rectiformers and the rectifiers. Both of these items can be readily found today in the collector market.

I had a Gilbert DC engine, we ran it with a normal 100W 4B transformer with a 5A selenium disc rectifier my dad bought at a local electronics store far cheaper than the Gilbert rectifier. I still have it, that rectifier is almost as big as the 4B transformer.

The Gilbert DC motors were the same design as the universal three pole open frame motors. A permanent magnet field is used in place of the wound field and the DC motor armature windings used more turns of a smaller gauge wire resulting in about 50% more resistance than the universal motor armature. The amperage draw of the engine was the same, between 1A and 3A depending on the load on the engine.

if you are interested in running vintage O scale 2 rail locomotive from a fixed location you may want to consider using a Lionel ZW with a bridge rectifier,  center off DPDT toggle switch, and a circuit breaker on the DC output.  Adding analog amp and volt  meters would be simple.