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Building an Operating Overhead Catenary System for “O” Gauge Model Railroads                       ....Continued     

By Thomas P. Leyden                                            (Return to Beginning)

Getting power to the “system”


Every layout is different!  Think ahead as to how many individually powered loops you wish to have.  In my case I have five (5). Each of these powered loops has to be electrically insulated from the others.  In most cases the insulator is “air.”  Rarely, a short length of black wire insulation stripped from a length of 24 gauge hook-up wire is placed on the catenary wire and slid to a point where two wires might touch.  (If this method is used be sure that the insulated wire is on top otherwise the pantograph might snag on it.) 

The separating point between power loops is usually at crossover or switching points.  At these locations care must be taken to insure wires from the two loops do not touch each other.  This will require two machine screw/tube “hangers” about ½ inch apart to carry the separate wires to the two loops of track.  If properly measured and installed the pantograph will wipe both wires for a moment as it passes from one loop to another.  The photos 20 and 22 on previous page show the double hangers in use.

Getting power to the overhead wire is really simple.  Drill an additional small hole (to accommodate wire) at the bottom of one of the “anchor point” bases.  Feed the wire from your power source under the table and then up through the newly drilled “base hole” into one of the “H” column channels and attach the wire to the screw eye holding the spring which has the overhead wire in tension thereby making a circuit.  One connection for each loop.  No need to have “jumper” wires to distant points on the layout.  My loop lengths are 100 feet.  The photos that follow hopefully clarify the point.

Note how wire goes up the “H” column channel and then is attached to the screw eye

Close up of connection


Installing Catenary on Moveable Bridges

Installing catenary over moveable bridges on my layout such as the Lionel Bascule Bridge or a removable bridge was the biggest challenge in the construction of the catenary system.  [I also installed the catenary in the Lionel Lift Bridge but that is much more complicated.  I shall include that as an addendum when I take photos and write it up.] Basically I viewed actual bridges of all types on the nearby Metro North (ex New Haven) railroad to see how it’s done in real life.  My system was patterned on what I saw.

Bascule Bridge
Since pictures speak louder than words I have included some photos below to help in the understanding.  First, install catenary bridge-supports at either end of bridge.  Approximately 10” from each of these are installed additional catenary bridge-supports.  1/8” brass rod is used to connect the two catenary bridge-supports and installed in such a way as to allow smooth transition from wire to the rod. I refer to these as “brass rod run-ups” or “run-ups.”

1/8” rod is affixed to ½” x ½” basswood sticks cut to fit in the trusswork on the top of the bridge.  Each of these basswood sticks has a 7/16” machine screw inserted in predrilled 7/16” holes in the middle of the crossover span.  Before installing in the bridge the rod is soldered to the machine screws at carefully measured locations to coincide with the location of the bridge truss spans, four in all.  At this point the rod should extend well beyond either end of the bridge.  It will be cut to proper length later. See captions under following photos for how to finish the “run-up” and on-bridge rod ends.

Right side of bridge.  Notice the device I fashioned to hold down rod as pantograph went by.  This insured a seamless, non-snagging path for the pantograph.  This is patterned after actual railroad usage.

Right side of bridge from the top showing design of the “run-up”

Close-up of “seamless” path on right side of bridge

Another close up of “seamless” path

Location of end of rod on right side “run-up” to insure it misses track in moveable part of bridge.  Important….measure carefully

Top view showing “hold down” device and wooden “spans” to which the brass rod is soldered

Detailed view of right side “run-up” where it “meets” the main wire catenary.
Notice the tube soldered to rod to allow wire to pass through to spring on other end of “run-up”

Detail of left side “run-up”

Left side “run-up” detail where main catenary meets “run-up”

Left side of bridge showing rod soldered to metal “counterweight” on the bridge.
Metal has to be stripped of paint to allow secure solder connection

This photo shows detail of the left side of bridge.  Note that the bridge rod is bent upward in such a way that when the bridge is lowered it makes contact with the bent end of the rod in the left side “run-up.”  The right end of the “run-up” rod must be bent slightly upward to insure a smooth snag less path for the pantograph. Adjustment of  the “hanger” on the right side of the “run-up” may be necessary to insure proper contact or there will be no power on the bridge.

Article Concludes with Removable Bridge

Second Decade.
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