This step-by-step will show how I improved the performance of my sound-equipped On30 Bachmann 0-4-2T Porter locomotive.
I enjoy running Bachmann’s On30 Porters, which are perfect for my mining-themed layout. When they introduced their Tsunami sound-equipped DCC models, I was delighted. Unfortunately, their small wheels and light weight cause the locomotives to constantly cut out on my track, making the sound decoder recycle frequently while stalling the locomotive.
I tried adding track wipers between the drivers, and tried using CRC-brand contact cleaner to keep the track and wheels clean. Both provided only limited success. After much experimentation, here is the solution that worked best for me. My solution was to add a short tender behind the locomotive, which provided two vital solutions to improve performance: added track pickup from the tender wheels, and a KA2 Keep Alive capacitor module from TCS. This combination has made my Porter a ‘bulltetproof’ performer, even on less than clean track.
The locomotive in this project has already had extensive modifications - a custom cab with overlays of lead sheet and styrene, considerable added weight, custom smokebox door, headlight, link and pin couplers, foodboards, detailed steam dome liner...and I plan to add additional details and weathering now that this construction work is done. I like to test my solutions as I go, so I wanted to get the basic tender built, add the pickups and capacitor module, then wire it up and test everything before completing the final model. That way, I could identify problems while everything was relatively accessible and easy to fix!
NOTE: This is a challenging project, if you are a novice to DCC I suggest you do some basic DCC installations before tackling this more tricky project. I have done a dozen successful DCC conversions, but fried the decoder of another Porter while finishing this tutorial because of a mistake made when I was tired and distracted. There is no substitute for careful, methodical work. Consider yourself warned!
Bottom line: you need a good, fine-tipped soldering iron, good soldering skills and a steady hand to avoid damaging the sound board or wiring. Read through this tutorial, follow the steps closely and double-check your work, and you won’t have any problems.
Here are the DCC-related tools you need: high-quality wire strippers (mandatory!), a multimeter (also mandatory!), gray double-sided sticky tape, shrink tubing (2- and 4-conductor sizes), a length of fine gauged DCC hookup wire, a good soldering iron, resin-core solder and flux. I made up a DCC-specific toolbox to keep these items handy. Of course, you also need a TCS KA2 capacitor module.
For the tender, you will need a Bachmann On30 passenger truck, A brass drawbar (I used one from Sonora Scale Models), brass washers and a nut/bolt set to connect the drawbar to the tender, brass strip stock for the journal braces, coffee stir sticks or comparable stripwood, and 1/4” square stripwood for the end beams of the car. I used Micro-Mark Tie and Bridge Stain on the wood parts, and gap-filling ACC to hold everything together. I also used basswood strips from my scrap box, and assorted details from Boulder Valley Models and Grandt Line. Most of these items I’ve had lying around waiting for a project, you may already have similar supplies to draw upon. I’ll mention more specific detail items in the tutorial. Let’s get started.
We’ll start by getting the basic tender completed to support DCC testing. Here is a stock Bachmann passenger truck next to my modified truck, which will serve as the frame for the tender. The Bachmann truck is a more modern passenger truck design with heavy coil and leaf springs, and an equalizer running between the journal frames. I chose to remove all that detail to back-date the frame to an earlier period.
1. First, disassemble the truck by removing the screws holding the sideframes on. Next, remove the hookup wire, and save it...you will need the metal connector in the next step.Using a sanding drum in a motor tool, I sanded off the center mounting bolster flush with the top of the truck frame. Then I used a motor tool with a cutoff wheel (wear eye protection!) and small files to clean up the cuts. I also filed the bolt detail of the face of the sideframes. Be careful not to break off the brake shoes and hangers, the metal is quite brittle and breaks easily. Don’t ask how I discovered that!
2. Here’s a close-up of the modified truck with wipers and connections added. Start by unsoldering the nickel silver contact lug from the original hookup wire, and solder a length of black-insulated DCC hookup wire to the lug. Then attach it to the near sideframe with the lug inserted between the screw and the tab on the sideframe.
3. Insert the wheels (with the insulated wheels away from you) between the sideframes, and attach the second sideframe to the truck. The insulated wheels have small black delrin bushings where they join the axles. Attach the second sideframe, taking care to insert the small pins in the delrin frame into matching holes in the ends of the sideframes.
4. Bend a length of brass wire to make pickups to wipe against the inside of the insulated wheels. Then solder it to a flat brass washer, using flux and pre-tinning the parts. Drill a small pilot hole in the center of the truck frame, then attach the wiper assembly to the truck with a small screw. You want a bit of tension between the wiper and the inside of the wheels. Once you have tightened the screw, adjust the wires so the wheels will roll when a bit of down pressure is applied by your finger. This is important, if the wipers are too tight the wheels will not roll, causing flat spots and a lot of drag for your little Porter to pull!
5. Next, drill a hole through the plastic frame to allow wires to be passed through to the underside of the truck. Using fine-gauge DCC hookup wire, solder a short lead (with Red insulation for Right Rail) to the pickup wire. Use a dab of flux and tin the wire and the tip of the lead before attempting to solder. You need a quick tap with the iron to prevent overheating the brass wire and loosening it from the washer.
Attach a brass drawbar using the small hole in one end of the truck. I chose to use a drawbar from the etched brass set produced by Sonora Scale Models, but you could also make your own out of brass or aluminum stock. I used a 00-90 nut and 1/8” bolt (Micro Mark part numbers 70201 and 70185 respectively) with a washer from my parts bin to attach the drawbar to the truck. Once tightened only slightly to allow some vertical play for the drawbar, I added a dab of gap-filling ACC on the end of the bolt to keep the nut in place.
Use your multi-meter to test the conductivity of both leads...set it to continuity check, and place one lead on the rail and one on the corresponding lead, then roll the truck for a foot or so. You should get a fairly steady tone from the tester that current is being picked up. Correct any problems if you don’t get conductivity before proceeding, this is critical to improve the Porter’s performance.
6. Next, add the decking and end beams. I simply cut coffee stir sticks to length (matching the width of the Porter frame). I also cut two lengths of 1/4” square balsa stripwood that was distressed using the edge of a razor saw for the end beams. These parts were sanded, stained, then glued to the frame with gap-filling ACC.
I notched the forward end beam where the drawbar will pass under the beam, just to give adequate clearance for the drawbar. In this view, the end beam is upside down to show the notch. Now is the time to plan for a rear coupler; notch the rear end beam as necessary and build a shim if using Kadee or similar draft gear. I added a Foothill Model Works link and pin drawhead on the rear of mine, with stripwood lengths on each side to simulate the draft gear framing under the car.
Here is the tender with deck and drawbar, ready for mounting weights and the KA2 capacitor module. I added brass strips for the braces between the pedestals. You can add nut/bolt/washer detail under these to simulate bolts going into the pedestals if you want; I omitted this detail, as these parts are so close to the ground I won’t miss the detail.
7. Next, I drilled a small hole in one of the deck boards to allow the wires from the capacitor module to pass below. I stuck two 1/4 ounce A-Line lead weights to the center of the deck. Then, using double-sided gray sticky tape, I attached the KA2 capacitor module to the lead weights. It may not look like much, but works just fine. Next, thread the two wires through the hole to the underside of the car.
8. Now it’s time to connect the car to the Porter. (These photos show the cab removed from the locomotive, which I did for detailing purposes...you don’t need to remove the cab to complete these steps.)
First, remove the two screws holding the rear bunker in place. (Save the parts in a safe place!) Unscrew the rear coupler, then attach the tender drawbar in its place, using the same screw. Because the locomotive and tender are so small, I chose to permanently connect them, rather than have bulky connectors in these tight spaces.
9. Add a short length of heat shrink tubing where the four wires meet under the tender. Then use a longer piece to simulate the water connection to the locomotive. Thread the wires through the tubing, pass the tubing through the slot in the rear pilot, and thread the wires up through the small hole forward of the coupler mounting screw. I am impressed that Bachmann thought of putting a hole here, convenient, eh? Check the fit of the tubing sections, then heat-shrink them to keep them in place.
10. The job of soldering the leads to the circuit board in the bunker is easier if you first remove the board from the bunker. (Note: this is not true for the 0-4-0T!). Remove the two screws marked with red arrows, and save them with your other Porter parts. The board will come free. There is a sticky insulated pad on the opposite side of the board, remove that for now and set it aside.
11. Now comes the trickiest part of the project...replacing the connections to the PC board. I suggest you use a non-conductive clamp to hold the edges of the circuit board while soldering...I did it the hard way, trying to hold the board in place while using both hands to solder the tiny wires. Lesson learned! NOTE: very little solder is needed for this operation, just lightly tin each of the wire leads and that’s enough to make these connections.
You should start with the capacitor connections. Unsolder the two wires leading to the terminals marked with the green dot in the above photo. These go to a small capacitor mounted in the Porter’s sand dome. Simply trim the wires back an inch or so and isolate them using a short length of 2-conductor shrink tubing...the stock capacitor will just ride up there doing nothing for the rest of it’s career!
(NOTE: IN THE BELOW DIAGRAM FROM BACHMANN, THE + AND - REFERENCES FOR E. CAP CONNECTIONS ARE REVERSED. I ACCEPT NO RESPONSIBILITY FOR THIS ERROR IN THEIR DIAGRAM. SIMPLY FOLLOW THE BLUE COLOR CODING, WHICH IS CORRECT FOR THE + CONNECTION. Consult the instructions that come from TCS, they correctly identify the blue wire as the + connection.)
Next, solder the leads from the KA2 as shown...blue (+) lead to the terminal farthest from the edge with the multitude of wire connections. Next, solder the black/white (-) wire. Do not get these wires crossed, it will ruin your KA2 and void its warranty, OR destroy the motor control module in your decoder! Double-check your work with the diagram before proceeding. Double check your work, then check again.
12 Next, we will replace the Right Rail and Left Rail leads from the PC board. Refer to the documentation that came with your locomotive. (Here is a scan of the board layout.)
We just replaced the two leads going to the terminals labeled ‘E.Cap’. We are now going to replace the leads at the Right Rail and Left Rail terminals.
Carefully unsolder the Right Rail lead. I found it was easiest to do this with a minimum of risk overheating the board by applying the heat to the underside of the connection, thereby avoiding a hot soldering iron inserted among the wires on the top of the board. Cut a 3” length of red hookup wire, tin the end, and solder it to the Right Rail terminal on the board. Then connect this wire to the original (black) wire you unsoldered a moment ago, and the red lead from the tender. It’s best to strip a 1/4” length of insulation from each wire, twist the strands tightly, then twist the three wires together and solder to make a good reliable connection. Then add a short length of 4-conductor heat shrink tubing to insulate the connection. (You can see these connections in the above photo if you look closely.)
Next, repeat the same process for the Left Rail (connecting to the black lead from the tender). Work slowly, and take care not to overheat the circuit board or let any wire strands or solder make their way to contact with another terminal on the board. Inspect the board and double-check everything is connected with no globs of solder.
13. Now it’s time to use the multimeter to test the connections BEFORE firing up the locomotive on the programming track! Unless you are fearless and don’t mind frying the decoder, you want to follow this step carefully!
Make sure no power is applied to the rails, then set the locomotive on a section of track. Using the conductivity setting on the multimeter, place one lead on the right rail, and the other on the right rail terminal on the circuit board. You should get a solid tone indicating a closed circuit. Repeat for the left rail. This ensures all is well. Test both leads a second time to ensure you have the right terminal positions. Once passing this test, you can safely test the locomotive. I suggest doing so on your programming track, to reduce the possibility of damaging the decoder by applying full power. Run through the diagnostic routine for your DCC system to test for shorts, then ensure all functions work, including motor, sound, headlight, etc.
14. Once testing is complete, mount the PC board back in its place in the bunker casting, being careful to gently tuck the wires back in place without any pinching against the metal edges of the bunker. Replace the two mounting screws. Make sure to replace the sticky insulating pad against the back of the PC board before positioning the board next to the metal bunker wall. (This is provided to insulate the ends of the wires from making contact with the metal bunker wall.) Then place the bunker in position and replace the two mounting screws to hold it in place.
From this point on, you should have a Porter locomotive that will perform flawlessly. Note that the KA2 needs a minute or two to fully charge. Of course, you will need to keep the loco and tender wheels (and track!) clean just like any other loco. From this point on, you can detail your tender and locomotive as you wish.
The locomotive and tender will now receive lettering, weathering and final detailing including cab details and a crew. Have fun making YOUR Porter bulletproof!
