I have a number of Key and other brand brass ATSF steam locos running on my layout including 4-8-4's, 2-10-4's and others. Here's how I improved their pick-up abilities:
1. Clean all the wheels. This should be obvious. Lay the locomotive inverted on a soft foam cradle and attach wires with small alligator clips to the frame and drawbar - make sure the drawbar cannot touch the frame or it will short circuit. Attach the other ends of the wires to an adjustable 12 volt DC power source. Now apply power until the drivers are spinning at about half speed.
Start out at extra low speed to make sure the motor doesn't have a dead spot in its armature, then resume power to half speed.
Next, twist the corner of a paper towel into a small pointed tip and dip it into lacquer thinner or alcohol. Lightly press the moistened tip against the spinning driver tires. Avoid the moving drive rods to prevent damage. Do this to all of the drivers on both sides of the engine. As the towel tip gets dark and dirty, make another tip and continue until no darkness appears on the tip. You'll get the most dirt from the drivers with traction tires.
Now clean the pilot and trailing truck wheels the same way (except you'll have to spin them with your fingertips.) Even though some of these wheels do not conduct power, clean wheels reduce dirt transfer to the others via the track.
Finally, clean the tender wheels. I do mine by pouring a small amount of thinner or alcohol on a sheet of paper towel and laying it on an expendable piece of track. I then roll the tender along this towel-covered track until no dirt shows up on the paper towel.
2. Next come the tender truck connections. Remove both tender trucks with a screwdriver while keeping careful track of loose washers and tension springs. Remember how they were arranged so you can re-assemble them correctly. Also, take note of which side the live and insulated wheels are on. Most brass engine tenders have their "live" wheels on the left (fireman's) side. Most brass locomotives have their "live" drivers on the right (engineer's) side. The insulated wheels are opposite.
Using No. 600 grit sandpaper, polish the mating surfaces of the tender body's bolsters, truck bolsters, washers, and mating surfaces of springs until they are bright and shiny. Make sure the springs have enough strength to press firmly against their mating surfaces. If there are any truck-to-axle leaf spring pickups present, clean thoroughly and adjust for firm pressure.
Finally, re-assemble the trucks to the tender body. Use a volt-ohmmeter to test continuity from each wheel on the left (fireman's) side to the drawbar pin at the lower front of the tender frame. If a wheel is dead, find the problem and correct (usually a build-up of dirt in the axle cup on the inner surface of a truck frame.)
One final note: Check to ensure all the tender truck axles are absolutely parallel to each other. Sight down the assembled axles (like a surveyor) from front to back to see if there's a "twist" visible in their arrangement. You may have to gently twist the truck frames back into alignment to correct this. Also, check to ensure that all wheels are touching the railhead when on the tracks. Correct as necessary.
3. Add a half-ounce to one ounce of stick-on lead weight to the interior of the tender. This allows the wheels to push tighter against the rail head and overcome minor track dirt.
4. Using moldable tungsten putty or lead, fill the interior of the locomotive's boiler shell with as much weight as possible which also improves the wheel-to-rail electrical connection. The boiler shell is normally removed by unscrewing two small screws under the bottom rear of the cab and a single longer screw under the bottom of the cylinder saddle. Be careful of headlight wiring when removing the boiler shell. Keep track of loose parts such as the pilot, boiler braces, and so on. Make sure the weights clear the drive shaft and gearbox inside the engine.
You can get tungsten weights here:
http://www.pinewoodpro.com/weight-sets.htm5. Clean and adjust the locomotive's drawbar. Remove the boiler shell as described above. Next, use tweezers to grip the brass drawbar nut while removing the screw from the bottom using a jeweler's screwdriver.
As they parts come loose, be prepared to catch the tension spring and any brass and/or plastic washers that fall free. Take note of how they are arranged so you can reassemble them correctly. The small brass nut is soldered to a thin flexible pick-up wire that leads to a motor terminal. Inspect the wire and its solder joint for strength and damage. Now clean the drawbar itself where it makes contact with the screw and clean the mating surfaces of brass washers and related parts as you did with the tender truck bolsters. Make sure all surfaces are shiny and bright. Make sure the "pressure wire" soldered onto the drawbar presses firmly against the tender's drawbar pin when connected. Adjust as necessary by gently bending it until satisfied.
Adjust the tension spring by stretching it slightly to make sure it presses firmly against the drawbar. Reassemble all parts in the proper order. Work on a clean table using an apron to prevent the loss of small parts - do NOT lose these small but vital parts!
6. Check continuity from each right-side driver tire to the engine's drawbar using a volt-ohmmeter. The connection should be solid under all conditions. If not, you may have to remove and clean the mating surfaces of the driver bearings and the frame. Another option is to add ultra-thin brass or phosphor-bronze shims between the removable bottom plate and the bronze bearing blocks to improve continuity.
Re-assemble all parts and make sure the drawbar is not shorted out to the locomotive's frame. Test with the volt-ohmmeter by connecting one wire to the drawbar and the other to the frame. There should be no current passing through. If it is shorted, the insulated washer may be missing or upside down.
7. Set up the engine for running and then run it over turnouts in both directions at low speed. Be sure to thoroughly clean the track before proceeding. If the unit stalls on the frog, check to see if the rubber traction tire is lifting the other drivers off the rail. On one of my engines, a traction tire was fitted to both sides of one axle and this caused some problems on turnouts. I removed the traction tire from the right (engineer's) side and the problem was solved. The left (fireman's) side tire was left on. Pulling power was barely affected and the engine shows no obvious signs of yaw under load.
These steps comprise all the methods I've used over the years to get my brass beauties to perform as good as they look. Nothing beats the nearly all-wheel-pickup properties of a Kato or newer Bachmann product, but using these tips will get your brass steeds to nearly match their performance.
