4-4-2 Typical mods/fixes

Repairing broken crankpins

This is probably the #1 issue on any Atlantic "new" or not.






Investigating, I found that the crankpin has plenty of threads all through it, and the chrome screw is almost an inch long so I held the broken end of the crankpin on with small vicegrips or a piece of heat shrink. I then drilled 1/4" down from the end with a drill that would give clearance to the screw threads for that first 1/4" (otherwise the screw would split it again). I then epoxied the split crankpin ends together. JB Weld worked best in this case. (It's a very hard and tough epoxy found at auto parts stores)Now with the valve gear running well, I proceeded to take the loco apart.

See the sub-page on a great way to repair/replace broken crankpins.


Improving the gear train:

The basic problem all Atlantics have is gear mesh, and the results vary from destroying gears, to breaking the siderods. There are two things that allow the gears to come out of mesh:

Problem 1: motor not held in place well enough

From the factory, there is a single cable tie holding the motor in place. George found that this single cable tie did not do an adequate job, allowing the motor to rock and lose contact with the gears. He used a second cable tie. I found the three fit even better, see below:


Problem #2: wheel down travel excessive, gears come out of mesh

Another problem George observed is that often the gearbox cover (on the bottom) does not limit the "down travel" of the axles, allowing them to disengage from the gear on the motor. This happens when you pick the loco up. This allows the drivers to "skip teeth", and then the drivers are out of phase with each other, and normally you break the siderods immediately.

After removing the bottom cover, you will see 4 small raised "lands" that are there to limit this travel, but normally, they are not limiting enough.

Atlantic bottom cover

Put the shims on the 4 "raised lands" - where the red rectangles are:

Atlantic bottom cover   bearings copy


George added 4 small shims the size of the lands in the bottom cover. They are places such that the axles will bear on when the loco is lifted off the track. He used shims of 0.020".

I checked my loco, my gearbox cover was also not doing the job. I measured mine and found that .015" styrene eliminated the slop. Since this only limits the "downtravel" of the axles, I believe styrene is fine (the axles only touch this when the loco is lifted off the track)

I strongly recommend checking this and shimming since it was easy to get the wheels out of phase. Again, when this happens, the connecting rods can be snapped in two immediately.


I added weight to the loco inside like George did, he added over 3 pounds. I found some perfectly-sized 2 pound weights (called "rock cod sinkers") and put one directly over each driver. There is plenty of space in the boiler. With these 2 additional weights, total weight of the loco is 8 pounds 10 ounces. With the drive train now properly engaged all the time, the extra weight really adds to the pulling power.

Additionally, it should help things if metal wheels for the leading and trailing truck can be obtained. Someone suggested that Aristo Pacific leading truck wheels and bushings are easy to add, and would provide additional power pickup without any additional drag. I will see what I can come up with.

Finally, adding weight to the tender seems to be a good idea, it's very light and could help avoid derailments from long cars with body mount couplers, like heavyweight passenger cars.





Replacing the pilot and trailing truck wheels, increasing power pickup

These are all plastic, and need more weight and this loco also needs better power pickup, so find a way to get metal wheels

They are plastic, yuck. The stock diameters are .955" for the pilot, and 1.625" for the trailing truck

Pilot truck

For the front wheels, he used metal wheels from Thomas the Tank rolling stock

At one time, I believe Gary Raymond made replacements for these. George Schreyer suggests FS133 are the front wheel replacements.

I saw some pictures of one so modified recently, looks like some weight was also added to part of the bolster cavity in the front truck.

Another modeller used big hauler pilot truck wheels, but used the 2-6-0 mogul center/insert. This modeller made brass U shaped pickups that ride on the metal collars of the wheels.

Trailing truck

The diameter of the stock wheels are 1.625"

Nico Corbo used a Bachmann Thomas spoked wheel for the trailing truck:

I'll get the part number and try it.

Another modeller used a drive wheel from an outside frame consolidation, and turned down the axles. Again he used flat brass riding on the inside "hub" of the wheels.

I got this email from Gary Raymond two years ago.  He might still have those wheel sets.

"Ball bearing wheelsets for the tender which would allow electrical pickup are 133RDSE. $15.95 each (4 required).

Ball bearing wheelsets with no electrical pickup are 133RDSN. $15.95 each (4 required).
Ridgid axle wheelsets are 133RS (Plated $5.95 each), 133BS (Black $5.95 each), and 133US (Unplated Steel $4.95 each). (4 required).
Two packs of washers are necessary for the tender wheelsets. Part# W031B and W063B. $0.69 for each bag. (One of each required).

We have the pilot wheelsets. 133RF but they will not do electrical pickup. $5.95 each (2 required).

We do not have the trailing truck wheelset (1.625" dia.). The largest we currently have is 1.280" dia. F26RS. $5.95 each. Some customers have been using our F26RS. However it is significantly smaller. 1.625" vs. 1.280". It will fit but changes the angle of the yoke. That can be corrected by lowering the pivot point of the yoke.
State tax if in Calif 8.75%
Please email or call for shipping."




Tender modifications:

The trucks on the tender look small, the wheelbase of the trucks is 1-3/4, the truck sideframes are about 2.3" long, and . The stock plastic wheels measure about 0.95" in diameter (tread diameter at the flanges) and the overall length of each truck is 2.9" (over the flanges). The axle tips are 0.12" in diameter. 

There looks to be room to have slightly larger truck wheels, plenty of clearance between the wheels and the underside of the tender, over 1/4".

I found good replacement wheels, the Bachmann 92422 "24.5 mm Small Metal wheel set". At the flanges the wheels measure out about 0.98" The axles are longer than the stock ones, but they snap in no problem. Be sure to gauge the Bachmann wheelsets, mine were undergauge, and I pulled one wheel and spacer off and then added a small washer in the center, reassembled, and that put the back to back spacing right on.

Now I needed to add power pickup. I was thinking of doing the "eyelet thing", like AristoCraft does on it's tenders and heavyweight passenger cars,  but the tender trucks have a rectangular slot the axles go into, not the typical round hole, so there was no easy way to get the eyelets in, and the bachmann wheels are insulated from the axle anyway.

I sat for a while looking at the trucks and a set of AristoCraft carbon brush pickups.

I finally figured out that if I milled a bit out of the AristoCraft pickup housing, and trimmed a bit off the tang of the Lionel truck, the brush pickup housing bolts right on with a 2-56 screw.

The tender also needs weight. Even after putting the big 3" speaker in it, it only weighs 1 pound 12 ounces.I'll add some more after I get a backup light in place.

Weather Underground PWS KCACARLS78