Brass Technical Tips
October Brass List 1997
"Help! It Won't Run"
Greetings from the Caboose Hobbies Brass Repair Department. This technical bulletin is the first in a planned series to assist you, the brass owner, in coping with the myriad of problems that can potentially raise their ugly little heads at the most inopportune times (e.g., the night before your layout's open house). These bulletins are intended to help you deal with problems that may develop over time in brand new models, as well as deal with maladies that may be present in 'pre- owned' older models.
Please note; while we do our best at Caboose Hobbies to test run every brass locomotive we sell, a 'stinker' does infrequently get away without our knowledge. Then too, parts and electrical connections can come undone due to the 'trauma' that a shipping carton may go through while on it's way to a customer (this despite the best efforts of our shipping department to pack models carefully and securely). In fact, it is sometimes wisest, if feasible, to fix minor problems at the destination, rather than expose the model to a double iteration of shipping trips, if it were returned for repair (which we are always happy to do, if needed and appropriate).
The scope of these bulletins will reflect the experiences gained over the span of many years, and will be as complete as we can reasonably make them. Bear in mind, though, that many topics are not finite in scope. There is always a new twist on a problem, or its cure, that even the Ancient Ones may not have personally experienced yet. Then too, brass model technology is certainly not stagnant these days. Consider the advances in sophisticated lighting and electrical systems that are becoming standard equipment on more and more models. In truth, we should be able to look forward to a continuing host of problem solving challenges for years to come (which avoids boredom, right?).
That said, let us get on with this, the first bulletin in the series.
Egad! You have just spent next month's family food budget on a coveted brass locomotive, have got it in the house, through household customs, down the basement, set it on the rails in avid anticipation and it WILL NOT BUDGE. This, despite successively heavier throttle applications, up to and including WIDE OPEN. Don't panic (at least not yet; the mate doesn't know yet that 'dinner' doesn't run).
First, don't assume the obvious and trust that everything is all right electrically on the rails. Take a second and plunk down your most reliable loco in the same spot, and see if it runs. Most likely it will, but maybe a toggle was thrown the wrong way or the like. Just try the simplest things first.
Okay, your favorite loco ran fine, so it is a problem with the new one; proceed to read.
You have to ascertain, now, whether the problem is mechanical or electrical. If you have an ammeter, you are in good shape to diagnose. If you do not, skip to the next paragraph. Now, does the ammeter needle move in relation to how much throttle you give it? If so, the model is drawing current and the motor is loading up, but not producing any mechanical rotation, and some sort of mechanical bind or motor problem is present. More on this aspect later.
An electrical problem usually manifests itself in two ways; an 'Open' (no current flow) or a 'Short' (uncontrolled current flow). An 'Open' is indicated on the ammeter by the needle staying at the zero amps position, regardless of throttle position. Note - a voltmeter will always show movement relative to throttle position, whether or not there is anything to draw current on the tracks, so do not be misled by watching the wrong meter. A 'Short', on the other hand, will usually produce full ammeter deflection with a small amount of throttle movement.
If you do not have an ammeter, you can still get clues from the power pack itself. If a Short exists, it will usually trip the circuit breaker in the pack itself, and will turn on a red warning light (if so equipped). If it is an Open, your pack will do essentially nothing. If you have the throttle open for 20 to 30 seconds, and the breaker does not pop, you have an Open, not a Short.
Now, more on the mechanical bind or motor problem conditions: A bind or motor problem will usually show up as an abnormally high ammeter reading, but not full deflection of the meter as a short would produce. In HO Scale, a normal reading for an open frame motor is between .3 and .7 amperes, and for a can motor, .1 to .2 amperes. About half these for N scale and about twice these for O scale. A reading above this (except perhaps briefly at start-up) indicates that more than normal current flow is being required to produce motor and hence locomotive movement. This is tougher to detect without an ammeter. It takes a 'feel' of what throttle position on your power pack usually will get a locomotive moving and how much throttle increase is required to attain a certain speed (Note, here, that there are various factors that can affect these, such as train length, grade, constant lighting, etc.). This area is not strictly a 'Does not run' condition; it is more of a 'poor operation' condition.
In any event, by this point you have hopefully determined what type of 'Does not run' situation you have; Open, Short or Bind/Motor Problem. So, here are some common causes for each, along with suggested cures:
CAUSES And CURES
* Dirty or oxidized wheels - Clean Wheels.
* Tender truck bolster pads dirty, oxidized or painted - Clean/polish pads.
* Tender drawbar pin dirty and/or oxidized - Clean/polish pin.
* Drawbar contact wire missing - Replace.
* Drawbar holes and/or contact wire dirty, oxidized or painted - Clean/polish.
* Drawbar screw loose under cab - Tighten
* Wire from drawbar screw to motor disconnected - Re-attach and/or Re-solder.
* Poor motor ground to loco chassis or disconnected wire from motor to chassis - Reconnect wire, tighten motor mount screws or reconnect wire .
* Poor wire to motor connections - Re-solder.
* Dirty or oxidized brushes or commutator - Clean.
* Dirty, oxidized or misadjusted pickup wipers on loco drivers (if so equipped) - Clean or adjust for proper contact.
* One tender truck reversed - Correct installation (un-insulated wheels normally on left side).
* Tender wheels (right) hit frame - Adjust or provide additional clearance.
* Tender wheel insulation failure - Replace wheel set.
* Brass or metal brake shoe assembly touches - Adjust or replace with plastic left side driver rims hangers and shoes.
* Failure of driver rim insulation - Repair or replace insulation.
* Wires inside boiler shorting.
* Lighting wires shorting - Find bare wires and insulate and/or replace.
* Motor wiring tabs touch firebox - Insulate or move motor forward.
* Truck sideframe touching insulated wheel rim or rail - Adjust sideframe or shim wheel end with insulated washer.
* Droopy details touching rail (e.g., air hoses, MU hoses) - Adjust detail (bend it up already!).
CAUSES and CURES
* Side rod or main rod hitting crosshead guide or other detail - Adjust crosshead or detail.
* Gear teeth engagement too tight or too loose - Adjust engagement.
* Flywheel binding on body part - Center flywheel on chassis and center chassis in body.
* Motor commutator/brushes dirty - Clean/polish.
* Motor 'locked' - Lubricate bearing and commutator with LaBelle 101 or Conducta-Lube and work rotation a bit at a time until free.
* Hardened lubricant on axles or in gearbox - Remove completely and re-lubricate.
You will have noticed that the listed 'CURES' often incorporate the recommendations to clean or lubricate. In actuality, there are quite a variety of useful methodologies and products to effect these. In fact, there is enough meat in this subject to probably warrant a separate and future bulletin. Suffice it to say, at this point, that there are a number of effective cleaning agents, applicable to the hobby, available at your favorite model railroad shop or hardware store. Always keep in mind, though, that most of these are CHEMICALS, and as such, should be used with appropriate cautions. Always read the information on labels, especially the warning and safety sections.
One aspect of cleaning is worth mentioning here and now. This is: DO NOT EVER USE STEEL WOOL of any form to clean model railroad equipment. The use of steel wool breaks off steel fibers into nice small bits, which tend to stick nicely to anything, especially motor magnets and lubricated areas. This residue is nasty to remove from mechanisms, so keep steel wool under the sink and out of the railroad room!