SSPRR Run Room

Playing with Toy Trains

Toy Train Layout Wiring - Switches, Page 2


Basic Intermediate Advanced Wire Management Bus Wiring 120V Train Room
Glossary Wire Sizes Switches Load Calculations Soldering Troubleshooting

Access Bridges used as Switches

(see Page 1,  Control Box and Track Trip)
(see Bridges Wired to Control Track Power with Relays for Engine Protection)

This method for powering bridge tracks and keeping trains from running into the open hole has
proven infallible. Using bridge contacts instead of plugging in bridge power is fast and user friendly.
The Lift Out Bridge is on the North end of the Lionel Lift Bridge.
Photos following the Circuit diagram show a variety of contact solutions.

4 Bridges

Two Bridges with 3 Sets of Switch Contacts
The through track located just South of the Industrial Yard has its power switched by the
Swing Bridge and Lift Out Bridge. If either bridge is out the Switched Track Section is dead.


2 Bridges as 3 Switches

Power is from Black Yard track and goes through bridges to south table.  The Purple is the
switched power and feeds center rails of the Switched Track Section.  The White/Common is fed
from the most convenient table.  The Red wire feeds the swing bridge because the Purple feed
from the south table track is switched as a siding on the Main Control Panel.

Circuit for 2 Bridges as Switches

Run Room Showing the North South rail line through the Yard and South end.

Main with All Bridges 

Swing Bridge on South End
The white, black, and purple wires on the left are secured under the bridge.  They slide
into fascia holes when bridge is opened.

Swing Bridge

Swing Bridge Swivels on Door Hinge

Door Hinge to Swing Bridge

Bridge electrical contacts need liberal tolerances to make good contact consistently.
Contact switches must be rated for voltage and amps used with tracks.
My Run Room is dry in the winter and humid in the summer causing significant contraction and
expansion in the tables.  Winter causes gaps and summer causes tight fits.

The Black wire contact seen from the west side of the
Swing Bridge is a magnetic cabinet door latch
with a flexible copper strap over the magnet.
Black Wire Contact
The Red wire contact was a copper strip on
both contact surfaces.  The strip attached to the
table required a loosely folded (springy) copper
strip backing to improve electrical contact.
The strip self destructed due to table expansion.
 Red Wire Bad Strip Removed

The Red Wire sliding contacts self destructed during the summer requiring a new contact.

Damaged Flexible Strip
Damaged Strip 
The 2 x 2 block was added to mount the catch's
contact plate.
Revised Red Contact 

Ace Hardware currently has 17 Magnetic Catches listed on their website.
A magnetic catch combined with a flexible copper strip works for positive bridge contact.

The first Purple contact failed.  The spacer
wood strip on the side of the bridge was added
for the L bracket to contact the magnetic
portion of a cabinet latch.
The Red wire contact strip was removed.
 L Bracket on Bridge
Purple Wire Contact
L Bracket to Magnet with Bridge Closed
 L Bracket w Bridge Closed

Bottom View of Current Swing Bridge Contacts
Red and Purple Switches Replaced.  Painter Arrival Pending.

Swing Bridge Contacts  Bottom View 

Swing Bridge with all Three Contacts Before Red Wire Contact was Replaced.
The White (outside rails) for Track is fed From the Other End of Bridge.

All Swing Bridge Contacts

Bottom of Lift out Bridge
The left end has Black and Purple contacts.  The right end has Black, Purple, and White contacts.
The magnetic latches used with the strike plates help secure the bridge during the dry winter.

Lift Out Bridge Bottom


The Above Plywood Bridge was Replaced in 2022 with the MTH 40-1103 Arch Bridge.
See that installation and wiring at Runner and Guest Access Bridges.

Arch Bridge


Question? Contact the SSPRR COO (Chief Operating Officer) using the email button to the right.  (If email link is absent, please enable JavaScript.) 


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