Just for reference, here's a 736 and a 2046. This is a later Berk with the plastic sided trail truck, headlight wedge, dull plated rods, and heat stamped number. The 2046 has the simplified bell casting, no decorative whistle, different position slot for the E-unit lever, and the one piece boiler front. Some of the earlier Berks also had the 3 pane windows like this 2046.

Berkshire736 004

Postwar 024



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Everyone raves about the 8-wheel worm drive of the 736.  But my own experience with them isn't that great...  The motor is geared only to the rear-most axle, and power is transmitted to the other wheels through the drive rods.  If the rods aren't lubricated, the holes wear wide, causing erratic operation.  The bushings of the rear axle also tend to wear in an oval shape, which causes the rear wheels to rub against the frame, and binding.  Even after substituting a larger 25-tooth worm wheel in 1948, the gear ratio is only 8.33 to 1.  This is pretty tall, which gives a high top speed, but not very much low speed torque.

Meanwhile the 2046 and 2035 have a spur-gear mechanism similar to the prewar 226, albeit with lighter-gauge aluminum sides and magne-traction.  The gear ratio is about 11-to-1.  That means more RPM and more torque.  The spur gears do a better job of transferring power equally to all six wheels.  Pulling power is mostly about the weight (and on steel rails, magnetraction) but unless the 736 is much heavier, I would put my money on a 2046 or 2035, especially on tight O31 curves.

As Lionel moved away from 1950, I do believe that tooling got worn, and manufacturing tolerances declined.  So a late-1950s 646 might not run as quietly as the original 2046.  My $.02

Build a better mousetrap, and the world will beat a path to your door!

C W Burfle posted:

Isn't the 2035 being brought into this thread a 'prairie' type 6 wheel driver.  The 726 & 736 are 8 wheel.

As is the 2046 Mentioned earlier. The 2046 uses the same boiler casting as a postwar Berkshire, but does not have a boiler front that opens.

I always noticed that the 2046 does not have the side marker jewels on the front classification lights above the boiler front, and the Berkshires did. Just one more thing differentiating the upper line engine. 

Dieseler posted:

A good maintained "46" berk with the dual worm drive with its drive train in good shape in my opinion cannot be beat ......

That's what I've always heard - the '46 Berk, the first Postwar, which had the dual worm drive, was the best of the bunch.

The other postwar steamer with a worm drive motor is the 746 N&W J. Per Greenbergs Repair and Operating Manual, "The motor and reversing unit of this locomotive are identical to those used in No. 736. The frame and drive gear are very similar to 736 and most of the parts are interchangeable." It uses the 2046 front truck.

In Roger Carp and Bob Kellers "100 Years of Toy Trains" (Kalmbach), they relate how the 736 Berk helped create the 746 J. "...O gauge enthusiast...John Van Dyck...starting with a Lionel 2-8-4 Berkshire...refashioned it in 1955 to resemble a J by creating a bullet nose for the boiler, adding two wheels to the pilot, and moving the drive rod to the second wheel." It spurred Lionel to develop the J for sale in 1957.

30 years later in 1987 Lionel introduced the Rock Island 4-8-4 Northern, a new boiler on the "tried and true chassis...of the...J..." (Greenbergs Lionel Trains 1987-1995 by Michael Solly) Two similar Northerns followed with the third (Northern Pacific) being a smooth runner with a well made Berk style motor. The first two had almost universally poor running Berk motors. The warning is not to buy one of those unless you test run it first.

Michael Solly also says the 1992 Mikado (Southern) uses a "...prototypically correct body, but still riding on the sturdy Berkshire frame." The later NYC and Denver and Rio Grande Mikados I suppose are also on the Berk chassis. I have the NYC version and someday I will check to see if it is a Berk chassis. Interestingly, these locos have can motors rather than the open frame AC motors of the Berkshire. The new Lion Chief Berk will use a can motor. Once it is delivered we will need to see it the motor mounting is the same as that used in the Mikado. And it will be fun analyzing this new Berk and comparing it to all the previous Berks, 2046s, Js, Northerns, and Mikados.

After reading all these great postings I would not be surprised if we are only "scratching the surface on what there is to know about the Berkshire and its relatives.


Jeff2035 posted:

The other postwar steamer with a worm drive motor is the 746 N&W J.


I knew I forgot one in my list! Thanks, Jeff.

Should probably also mention the MPC engines based on the Berkshire mechanism such as the UP, Southern, Great Northern, etc. engines. These were Berks, Mikados and Northerns, in that order, if memory serves me. These ran just as well as the postwar Berks they were based on.



Correction. Before leaving for work I checked my NYC scale Mikado (same design as Solly referenced Southern Mikado of 1992) and it is definitely not on the Berk chassis. The wheel base on the new Mikados is much longer than the Berks and also have lubrication ports. 

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