Getting the 783 Hudson (Nemesis) running as it should

This was a 783 and tender, in the box and never run. Sitting for 20+ years. With the high stack, higher torque, engine along with the engines weight it should pull well. First you have to get it to where it can pull itself.

First the Tender

DO NOT RUN the tender until you have checked the board inside.  The circuit board was held on with 2 layers of double back tape.  Tender base, double back tape layer 1,  aluminum sheet, double back tape layer 2 and then the circuit board. The original double back tape had rotted. It wasn't holding anything.  If I had run the tender as it was the sound board could have shorted.  The double back tape layers were replaced with new, high grade double back tape.  It was work to clean off the old tape to save the aluminum sheet. 

 It was assembled as before with new double back tape. Including the wire from the speaker to the plate.  When done the sound worked. 

There is a black wire from the speaker to the aluminum sheet.  Just bare wire end held against the sheet with the double back tape.  I calculate it is for some capacitor type action.


The chug is "noise generator" type chug.  The whistle is first gen.   It works.  The grand kids like the funny whistle sound.  Upgrading the tender sound system may be the next project.  

Fixing the engine

First out of the box, the engine wiring was poorly soldered,  2 wires hanging by a thread.  That was fixed first.

When the engine ran, the motor made a lot of noise.  The worm shaft would push the motor shaft back into the brush plate. It was a high stack from the factory, but only a single thrust bearing inside the motor.   The tolerance around the motor shaft and the bearing seemed very loose.  With the motor out of the engine and running by itself, the motor shaft rattled.  Anew 773-200x high stack motor as it was labeled was installed.  They come with single thrust bearing or dual thrust bearing.  The dual thrust bearing was used, with thrust bearings inside and outside.  This shows the thrust bearing on the outside with the C clip holding the bearing and shaft in place.

How much axial play should there have been in the worms shaft assembly, .010"/0.25mm.  How much was there?  .05"/1.5mm or so, it was obvious. Thin spacer washers (671M-23) were added until there was .010"/.25mm axial play. About 1 spacer washer thickness.  The vertical distance was good, no binding in that direction when the 2 brass blocks were level with the top of the casting.  

The worm shaft clearance where it connects to the motor with the rubber block was too tight.  Various combinations of 2 motors and 2 worm shaft assemblies did not correct it.  It was the same no matter the combination.  There was a problem in the main casting with the  distance from the motor mount to the gear box.   This caused the shaft to push into the brush plate on the original motor.  With the new motor,  and the 2nd bearing preventing the motor shaft moving axially, it bound up.  20% was cut off the length of the rubber block and the pins were pushed into the blocks a little to get the right adjustment. 

Once the clearance was adjusted, it ran well and much quieter.  It has all new modern grease and correctly oiled.  

The gears and wheels were good.  The linkage needed adjustment. The eccentric rod would catch/rub on the eccentric bolt head.   The bolt head looks like it has the same clearance as the original 773.  The eccentric standoff connection for the eccentric rod was a little shallow.  Adjustments were made to make the eccentric rod clear the eccentric bolt head.  

I found later that not all 773 eccentrics are made the same.   See Stage 2 Below

The smoke rod needed a little adjustment so it wouldn't bind the linkage.  A small bend in the linkage contact was all that was needed to make sure the linkage ran smooth.

The smoke unit was weak or non-functioning. There was no packing in the smoke unit.  I have another engine similar era, same smoke unit.  No packing in it either.   Same problem with that engine also.   It would take a lot of fluid to fill it enough without packing.  Then the smoke unit would have a hard time heating up in a pool of fluid. Packing was added.  It has been run and shows burn spots in this picture where it contacts the heat element.

A postwar smoke resister was used for the unit element.  It can be made to fit like original and within the packing correctly.  Now good, long smoke production.  Steam chest and Smoke stack. 


The 783 now runs almost as good as an original 1950 773, but the engine is still noisier.  It smokes well out of the stack and the steam chest.  It does what it should have done out of the box. It doesn't run as fast as many engines, it has low gearing.  Fast enough now to derail on  36" circle track at full speed from time to time, while pulling 5 cars.   

Stage 2

This is a picture of the original style eccentric for the 783.  Notice how the arm is straight.  Also notice the length of the steel sleeve.


This is a picture of a 773 replacement eccentric.  Notice the angle on the arm that will let the linkage clear the bolt head.  This version did not come with the steel metal sleeve.  

You have to put the sleeve on the eccentric.  As with many hobby parts it does not fit out of the box.

First check the length of the sleeve.   Make sure it will not cover up the nubs that engage the slots in the wheel.  I had to file about .010"/.25mm off the length.

Heating the sleeve and pressing did not work, too tight.  I had to carefully sand/file down the eccentric diameter until I could get the sleeve to press on.  About .002-.004"/.05-.1mm on the diameter.  DO NOT file/sand the nubs down by accident.  

After fitting, assembly, cleaning and touch up paint.  Notice how the sleeve fits to the top.


I put 2 of these newer eccentrics in. The original eccentric pins were pressed into the eccentric.   The new ones I purchased were loose, a slip fit, but they had the hollow ends. 

I used my auto center punch tool to set the ends of the rivets. A few hits and the eccentric rivet was set.  You need something hard backing up the head of the rivet or it wont set well.  If you don't want the eccentric pin to spin at all a dab of epoxy glue on the back  where you upset the rivet should do it.

Put them both in.  The factory 783 eccentric bolts had some locking style adhesive on the threads. I put a little on the threads of the bolts when I re-assembled. A drop of oil for lubrication and running good.  Everything clears without bending or tweaking anything.   

Stage 3

Well it ran for 20 minutes and then another part failed.  The drive pin on the center drive wheel.  It just sheared off.   No binding, no reason.  Manufacturing defect or over stressed during assembly?  Who knows.  The bolt was NOT bottomed out.   It also sheared off the drive dogs of my new "correct" eccentric when it failed.   Ordered some more good eccentrics and a new drive pin.

I pulled the wheel and found a small but strong knock out pin to drive the old pin out from the back of the wheel.  Too big of a knock out pin may enlarge the hole making the wheel useless.   Note the step on the hub of the back of the wheel.  The wheel still looked good, and would press back on well.   At least once more.   


The new pin.

You must put a  flat shim of some sort behind the wheel, off the hub.  So the wheel is flat when you press in the new pin.  If it goes in at an angle it could crack or break the pin or wheel.   Using my press and 2 flat anvils and some shim material on the back of the wheel I was able to press in the new pin.  It is strong and straight.

I pressed the wheel back on tight.  There were grooves from the original assembly.  I was able to index the wheel exactly as it was.  Perfect alignment, everything works well.  

Running the engine for 20+ minutes.  Runs great, no binding and running smooth.   Running for an hour, no problem.  Hopefully the nemesis name can be forgotten.


The original 1950 773 has a standard Pullmor motor and runs and pulls just as well.  No tune up was needed for the 1950 version.  Precision, tolerance and fit makes a big difference.

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Last Update Feb 26 `2022