21 Collectable Model Trains: Cars: How do Lionel UCS track sections work?
Description
This article is from the Model Trains FAQ, by Christopher D Coleman with numerous contributions by others.
21 Collectable Model Trains: Cars: How do Lionel UCS track sections work?
The UCS (universal control section) and its predecessor the RCS
(remote control section) and their O-27 cousins are simply
constructed, but operationally difficult to understand. The different
rails and the electromagnet operate in different ways for different
functions. As shown below, the section controllers use strips of
copper contacted in certain ways such that the desired circuit is
made. Either the three *s are connected or the two #s and the two
@s. The controller uses four wires. Two are connected to the rails as
supply and ground and the other two lead to the control rails and
electromagnet. Therefore only the two control wires need be strung to
your track while the others may be connected directly to the
transformer.
Uncoupling requires either the use of an electromagnet on a
plunger activated version or the energizing of asknuckle
electromagnet connected to ground and to a sliding shoe. The
uncouple button connects both controlsrails and the track
electromagnet to the power rail. This has the result of
uncoupling all types of couplers, ifsproperly positioned.
Earlier operating cars are supplied both ground and power leads
through a pair of sliding shoes, one in eachstruck. When the
Unload button is pressed, one rail is connected to ground and the
other to the power rail, thusspowering the car. Later cars used a
large spring loaded plunger in the center of the car to supply
the action,swhich must be manually reset after operation. The
Uncouple electromagnet must be used for these.
UNCOUPLE UNLOAD
RCS
near rail supply ground
far rail supply supply
UCS
left rails supply ground
right rails supply supply
electromagnet on off
6019 (O-27)
left front rail supply ground
right rear rail supply ground
electromagnet on off
OTHER O-27 SECTIONS
electromagnet on off
</pr>
UNCOUPLE UNLOAD
______O___________O______
| *-----------+-------@ |
| *----------+|-------@ |
| *---------+||-------# | front view
| ---------+|||-------# |
|___________||||__________|
||||
||||____4
|||_____3
||______2
|_______1
RCS CONTROLLER
top views
================================================== ground rail
-------------------------+-------------------- outer control rail
===========================|==+=================== power rail
----------------------+--|--|----------------- inner control rail
=====================+==|==|==|=================== ground rail
\ O O O O / screw terminals
| | | |___4
| | |______3
| |_________2
|____________1
RCS TRACK SECTION
=============================================== ground rail
left ----------------+ /~~~\ -+-------------- right control rail
==================| ( O ),+=|================ power rail
left ----------------+\ \/__// /+-------------- right control rail
=================+==\/===/==/================== ground rail
\ O O O O / screw terminals
| | | |___4
| | |______3
| |_________2
|____________1
UCS TRACK SECTION
=============================================== ground rail
__--~~~--__ +------------- right rear control
================== O =/=+============== power rail
--------------+ ~~--/__--~~/ | left front control
===============+=\===/======/===|============== ground rail
| \ / | |
| | | |__4
| | |_______3
| |_______________2
|___________________1
6019 TRACK SECTION
=============================================== ground rail
__--~~~--__
================== O ==+=============== power rail
~~--/__--~~ |
=====================/=========|=============== ground rail
/ |
| |____4
|________________3
OTHER O-27 SECTIONS
Hey, one coupler opens when I try to unload my car
The 3462 Automatic Milk Car, the log dump car of the same vintage
had coil couplers and these aresSUPPOSED to uncouple (which one
depends on the orientation of the car) when the car is
unloaded. Thesreason is that the sliding shoes provide power to
both the car mechanism (one positive one negative) and to
thescoupler coils (both positive, grounding through the truck
frame). So, whichever truck is contacting the positivescontrol
rail when UNLOAD is pressed gets uncoupled. UNCOUPLE gives
positive to both control rails, hencesactivating both couplers,
but not the car mechanism. This also explains why the truck can
get hot, as where thescoupler coil is on whenever the activatior
coil is on.
To get around this you'd have to cut the wire from the offending
coupler to the sliding shoe and always run thescar in the same
orientation (which would be mandated by the position of the
platform). The coil could besreactivated and work "properly" by
connecting it to the sliding shoe on the opposite end of the
car. This ailmentswas resolved by the adoption of mechanical
couplers.
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