The Pennsylvania Railroad reportedly never owned any S-2 Northerns. The manufacturer of this model, Con-Cor, has a habit of slapping "PRR" on anything they produce, and I fell for it. I bought it before I did extensive research. The model was released in 2002. The locomotive looks very well detailed. For the first five minutes it ran great, but then several moving parts started falling off. The tender leans to one side. The locomotive wobbles going down flat track. It has no flywheel so it is totally unforgiving of dirty track. Finally, after the mechanical problems were resolved, it started stuttering with getting little or no movement out of it. Polishing the wheels made a significant improvement. All in all, a beautiful engine, but a serious quality disappointment for the price.
I had problems running the engine. What I thought was a contact problem turned out to be two problems. First, I had completely forgotten to clean the wheels prior to running the engine. The wheels were literally covered in grime! Secondly, my model has a serious mechanical problem with its running gear. The side rods fall out and bind up the wheels. This photo is an extreme close-up of the problem. This was the mechanical problem I experienced immediately after installing the decoder. After about 15 minutes of working on it, I got it fixed and the engine ran nicely for about 5 minutes. Then it completely locked up again, with the same problem. The area where I placed the orange circle in the photo is where the problem is. The L-shaped bar is supposed to be vertical (in this picture). For some reason it keeps popping out, which puts tremendous side-ways pressure on the wheel and causes the locomotive to derail and stop running. I finally fixed this mechanical problem. I repaired it one more time only this time I paid close attention to where the plug in the wheel needs to go. I subsequently ran the locomotive for an hour or two with absolutely no problems. As a matter of fact, I think the engine seems to run better the longer I run it. I don't know if that is just perception, or if it is a side-effect of the motor and gears getting worn in. Two of the three sets of wheels on the rear truck of the tender are not in gauge. The rest of the wheels are.
The engine had been in storage for several years since it was last run. I couldn't get it to move but maybe a quarter inch at a time. It was horrible. The track is clean, and I cleaned the wheels, but it made no difference. After researching on the Web, and reading many others' similar problems, I learned that the wheels of the tender may need a deeper cleaning. They looked corroded! I figured they needed to be polished. It made a tremendous difference. What I don't know is if this is something that has to be done on a regular basis, or if it is a one-time thing. I don't remember what the wheels looked like when I bought the unit. (update: yes, this has to be done regularly!) I started by removing the decoder and PC board (remove the two small screws), then unclipped the weight in the bottom of the tender (see the parts in the DCC installation article). The rear truck is held in place by a clip. Use a small screw driver to punch one side of the clip back down the hole. The other will fall through. The front tender truck is held in place by a screw. It also holds the drawbar and the electrical connection between the tender and the engine. Shown here is the Dremel polishing "bit" that I used. I started with the softest bits, until I got to this one. This polisher actually worked. After removing the wheels from the truck, I gently polished the wheel thread until it shined. Watch out for the plastic parts on the inside of the wheels.
Every part in the tender seems to be excessively lubricated, even the parts that are supposed to make electrical contact. The brass bar shown in the next photo is how the track power is transferred from the wheels to the contact strip inside the bottom of the tender. I cleaned it off. The two wheels in the photo show the before (left) and after polishing (right). Quite a difference! After doing this for all the tender wheels, the locomotive started running right away. The front truck of the tender doesn't make good contact with the rails, but when I put a temporary weight on the front of the tender, the engine ran without stalling. I didn't polish the engine's wheels. I have not looked, but from what I read on the Web, there seems to be only minimal electrical contact in the engine itself. These models really get their track power from the tender. My project here seems to confirm that.
Why write a dedicated page for a plug-n-play decoder installation? Well, it proved to be one of the more difficult installations I have done to date! No kidding! Looking back at the process, this locomotive is wrought with problems. The exploded diagram that comes with the locomotive looks like it has been copied a few times too many, so it is very hard to see any detail. The "documentation" has lots of photos about how to correctly position the plug-in decoder, but absolutely nothing about how to take the tender shell off! There is only ONE WAY the decoder can fit in this tender. Helloooo!!!
I went to my computer and searched my personal archives of e-mail messages from the various mailing lists to which I belonged, and found one where someone gave some hints about how to remove the tender shell. I will try to describe it here with the help of some photos. The tender shell is held to the bottom of the tender at four points. There are two tabs, one at the front and one at the rear (see photo below). In addition, you will notice that the two rear ladders are inserted into the back of the tender body. Pry the ladders from the tender body. The front of the tender top popped loose right away for me (and the extra piece shown in the photo fell out right away). The rear tab is visible under the rear truck. Push the tab toward the front of the engine with a small screwdriver and the shell should come off. I had to pry the top of the shell off with a slight persuasion of the screwdriver.
I unplugged the dummy plug and inserted the decoder as far in as it went. The circuit board in the tender is in there quite loose, so you will want to provide some kind of counter force while removing the dummy plug and installing the decoder.
By this time I had spent a good 20 minutes already. I figured that re-installing the tender body was going to be easy. WRONG! This part took even longer than the disassembly. There were a number of problems that I encountered. The e-mail I referred to above didn't indicate these problems, so it might be different for your model. I snapped the piece that had fallen off of the front of the tender body to the tender body. This guides the wires to the locomotives, so it helps to have that stay in its place. When I attempted to install the tender body, I noticed that I could get either the front or the rear tabs to engage, but not both. Something was blocking the path in the middle. I suspected that the decoder wasn't in all the way. I tried to push it down into the socket, but it didn't budge. Then I noticed that there is a weight glued to the underside of the top of the tender shell. This was interfering directly with the decoder.
I decided to remove the weight from the body. It looks like it is glued in place with some rubber cement like Walthers Goo, so with a small pair of pliers I was able to break the weight off without damaging the tender body. Before I did that, though, I disassembled the rest of the tender body, which helped in figuring out the problems. This photo shows the parts. After removing the weight, the part that held the weight fit over the decoder nicely.
I reassembled the three pieces shown above and noticed that the tender body still had the same problem. It turned out the middle part (in photo above) didn't fit with the decoder installed. This next photo shows the problem.
I marked off the area of material to be removed and grabbed a knife and a file and went to work.
As shown in the photo below, the walkway didn't slide back into the notches in the top of the tender body because, you guessed it, the decoder is in the way!
Back to the knife and file and I removed the two clips and filed down the remaining stubs on the walkway. There are two tabs on the right-hand side of the walkway, so they provide the grip to the tender body. So, as you can see, not at all a plug-n-play situation. Substantial amounts of work must be done, including damaging the internals of the model to get this decoder to fit.