43 Collectable Model Trains: Maintenance Tips: My locomotive won't move.
Description
This article is from the Model Trains FAQ, by Christopher D Coleman with numerous contributions by others.
43 Collectable Model Trains: Maintenance Tips: My locomotive won't move.
There are many possibilities. First take your test light or
multi-meter, or a lamp post or other small accessory with two leads.
With the power on, first test directly at the transformer. If there is
no result, there is a defect in the transformer. Transformer repair
can be dangerous and should not be attempted by an amateur. Check next
at the track. If no response you have a bad connection to the
transformer or dirty track. If this tests OK check your engine wheels
for dirt or grime caked on. If all these test OK you may conclude it
is your locomotive.
To start working on your engine the first thing you need is an engine
cradle. You can make one by assembling some 3/4" plywood strips to
form an upside-down U or trough about 12" long and an interior of 4"
wide and 4" deep. Coat the interior with clean foam rubber or thick
felt. This provides a soft cradle for the top of your loco when you're
working on the bottom. Next you need an exploded diagram for your
loco. Greenberg has books of these for many makers. There are many
different designs employed in locomotive construction so the following
procedure is necessarily vague to cover many types of locos. It gets
progressively more mechanical from here.
To access the interior of larger steam locos there are often four
screws under the frame screwed upward into the shell. Many mid-sized
Lionel steamers use a rod through either side of the shell, just above
the rear driver, to keep the shell on. To remove it use an
appropriately sized punch and hammer to GENTLY drive it in one side
and out the other. Drive in the direction in which it moves most
easily. Newer diesel shells have two screws, one in each end of the
plastic shell just above the frame (visible). Older style diesels have
a rotating tab connected to a screw head under the frame at each end
of the body shell. Rotate them 1/4 turn counterclockwise to disengage
the tab from the shell. WHOA! Don't remove that shell yet. On many
locos there will be a wire connecting the light in the shell to the
frame. Be careful of this. On many Diesels the stamped steel railings
will scratch a deep grove in your precious shell. Insert 3X5" cards on
either side of the cab between the shell and railing first.
After removing the shell you should see the motor and sequencer
(Flyer's sequencers are in the tender, if steam). Find the lead that
comes from the roller or insulated wheels. Run a wire directly from
the transformer to it before the sequencer and connect the other to
the frame. If the motor now runs you have bad wiring in your pickups.
If not try the field lead not connected to a brushwell (see motor
diagram below). If the motor runs either the sequencer or sequencer's
wiring is awry. If it does not run then the problem is with your
motor. For sequencer trouble, see the sequencer section below.
This section covers universal AC/DC motors not DC only can motors. Can
motors are a steel can with plastic ends. Universal motors are open on
one side and have the wire wrapped field coil on the other and are
much larger. See the motor sections for more details on this. Lionel
universal motors come in two types, spur and worm geared. Worm geared
motors will usually be mounted vertically or diagonally and have a
corkscrew gear on the armature that mates with a gear with diagonal
teeth. Spur geared motors are mounted horizontally and are usually
used in mid-range to cheap steamers and cheap diesels. They use only
gears with straight teeth. Some motors are more readily disassemblable
than others. If it's won't come off, chances are it was never meant
to. Worm gear motors are usually easier to service than spur gear
motors.
To service your motor, first remove screws or nuts holding the
brushplate on. BE CAREFUL when you remove it. There is a delicate wire
connecting it to the field coil. If you break it off at the coil
you've ruined the motor. Also the spring loaded brushes will pop out,
so be ready. You can now see the three segment copper commutator.
Inspect it for dirt or pitting. Clean it with zero residue cleaner or
track cleaner, or if it is worse a soft pencil eraser. NEVER use
anything harsher or abrasive. Clean the ruts between plates with a
toothpick. Similarly inspect and clean the brushes, springs and brush
wells. If pitting has occurred the part must be replaced.
Not all armatures are removable but if yours is, do so and look into
the gear cavity (for worm-gear motors). Remove old dirty grease as
best you can and apply a thin coat of fresh grease. Look for worn
gears. The gear that meshes with a worm gear is the most common to
wear out. If you have a spur gear loco (mid to cheap steam locos) the
spur gear of the armature is likely exposed in the opposite side of
the loco from the brushplate. Again, remove old and apply new grease
to all gears, including those on the wheels.
T T screws
___O__^__O___ brush wells and armature bearing
|_____________| brush plate
O O brushes
____|____ commutator
| | | | armature windings
|_|___|_|
I
I armature shaft
O armature gear
H H mounting studs
+==============+ motor housing (field core)
|==============+--------+
|==============| | field coil
+==============+--------+
GENERIC UNIVERSAL MOTOR - EXPLODED VIEW
Reassemble the reverse of how you disassembled but watch to mesh gears
properly and if the brushes have grooves for the brush springs make
sure they are properly aligned and right-side-up. When reconnecting
plastic shells DO NOT OVERTIGHTEN!!! This will cause the shell to
crack immediately or over time.
DC can motors are generally unserviceable and should be replaced if
they fail. They are usually mounted in the trucks. A drop of oil on
the end bearings will help if they are exposed.
Similar procedures can be used when servicing motorized accessories
and whistling tenders.
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