Heavy Electric Modular Group

[Green_Elite_Cab]

Its been a few days since I updated this, but work has been going on-

Cross-spans

Both cross spans are done, though I am concerned over the strength of the steel construction. The solder joints do not seem to be holding well. If I have time after everything else, I might make new ones with Phosphor Bronze, and then pray I can "swap" them easily. if it doesn't work out. If it weren't so close to show time, I probably would re-do it. I might replace the vertical portions of the Cross-span with phosphor bronze (one at a time to maintain shape), so that I can keep the horizontal strength of the steel wire, while still being able to attach the catenary wire easily to the span.

I might install the the "steady Rods" on the cross span before I install them into the pole. This would be a departure from the recommended practice, but in this case, I have my catenary so thoroughly planned out, that soldering them on the work bench would be MUCH easier then attempting to solder them together in the air.

I will let there be excess on the steady rods, and slip the catenary wire onto them. Once its soldered, I'll cut off the excess. the steady rods will naturally intersect exactly where they should, since I'll solder and adjust them based on the drawings I've made. I just hope that the phosphor bronze steady rods will solder to the steal cross spans easily.

This a photo of the second span. Notice that the horizontal insulators are positioned differently than in the first. This was also the case on the prototype. It seemed that in most cases, all insulators faced the same direction, with the petticoats point towards one pole, EXCEPT for the last insulator on the other side, which would point towards the other pole.

In this case, the insulator between tracks 2 and 1 faces to the right, instead of the left as it does on the other installation. Normally, such details wouldn't make a difference to me, but then again, catenary is a very "repetitive" piece of infrastructure, and sometimes those little difference stand out.




Catenary Wire

This has turned out to be one of the more time-consuming tasks. My original jig was simply not up to the task of constructing 5' lengths of catenary wire. The original jig was built with my 4x8 in mind, and is great for constructing wires up to 4' long, with 2' catenary pole spacing.

I wasted considerable time trying to make it work for my 5' spans, before I gave up on it. This necessitated the construction of a new longer jig, which took a couple hours to complete, as the guiding "pins" needed to be installed properly so that they spaced the wire without being in the way of clip and hangar soldering joints.

Construction was further hampered by the nature of the materials used. For the Auxiliary and Contact wires (the pair of parallel wires in the PRR system), I used 3' lengths of 0.020" Phosphor Bronze.

In order to avoid weak "butt joints", I overlapped the wires. However, because of the length, these 3' pieces only overlap for 1'. This requires two 2' pieces.

This means that while there was technically over 20' of Phosphor Bronze in the tube, some of that wire could not be utilized for this purpose, resulting in the necessity of additional wire. Fortunately, my hobby shop had one last pack of straight Phosphor bronze.

In this photo, you can see the "overlap". The precise locations are marked by the vertical lines with the dashes next to them, indicating the overlap zone. This is so that I can position my wire precisely in the jig and tape it down so that it doesn't move while I solder them together. As it worked out, the "butt" joint between individual wires were not near any other major soldering joints, so they have a low risk of "popping" under heat accidentally. so far, they have not broken, but they might need to be polished smooth to promote better pantograph travel.

The jig is built on a 6' 1x4 plank. Straight pins are used to space the wire and retain them within distance of eachother. Tape prevent the wires from moving significantly. A drop of Tix Flux and a quick blob of solder does the trick. In the future, it may be "cleaner" to actually use small wires as clips, but this is faster and effective, if a little messy. If I have time, I'll file down the clips before installation.




The next step for the catenary wire is building the "messenger and Hangers", which are the "suspension bridge" components supporting the auxiliary and Contact wires. This step would normally be done the same time as the other parts, except that the Hand Place Overpass with interfere with the "typical" Profile of the wire.

The "Profile" is the actual spacing to the hangars, and the precise positioning of the messenger wire.

The PRR actually kept detailed drawings of all profiles of its catenary sections, however, I could not find one for North Elizabeth. Still I have plenty of examples of various situation from other parts of the Northeast Corridor, so it is easy to make some educated guesses, and photos help considerably.



Hand Place Bridge

I have finally settled on a bridge width of 27' 6". The way I figure it, this will allow me to closely approximate the dimensions of the prototype.

Using Google Street View as a guide, I assumed the pedestrian overpass was about the size of a standard sidewalk, and then I assumed the roadway had about enough space for 2 cars traveling side by side, with no shoulder. Next I guessed that the bridge girders were about 1/4 the width of an automobile. This let me get a "close enough" idea, and so even if it isn't perfect, those relations will probably work out and most people won't notice.

The other dimensions, such as length and height, were No-Brainers. The height would be determined by the distance between the bottom of the bridge and the catenary wire at a scale 22' off the rails. I sketched this out to actual size on the back of my Catenary pole drawing to ensure all things were lined up the same. The 1' length of the brass pieces conveniently allows space for the platforms and stone abutments, but doesn't go so far as to interfere with the scenery.

I cut the brass sheets and began soldering them to the brass angles to make the "deck" supports of the bridge. Today when i get home, I will make the catenary anchor brackets, and then build the "legs" and base. The majority of the work will be over once these components, and the catenary wire is done.

Anchoring and Final Assembly

Tomorrow, I plan to anchor the catenary poles to the module, and then assemble the catenary. I am not quite confident in my plan to anchor the poles, but at this point I'll have to figure something out or be out of luck.

Once the poles are anchored in, I can install the cross spans permanently into the poles, and then I will solder the wires to the cross spans and bridge anchors.

So far as I can tell, this might take all day, but it is entirely achievable. It also helps that I will be able to leave work early tomorrow, and will have most of the day to finish this.

I will definitely be packing most of my soldering supplies with me to make repairs at the show, since I'm sure there will be damage. Hopefully, nothing too severe!