Welcome to the forum!

The switch on the locomotive is for the electronic reverse unit board only. By moving the switch, you locked the engine in neutral. Slide the switch to the original position to get the locomotive to run and sequence again.

To lock the engine in forward, sequence the engine with the transformer to go in reverse, then into neutral. Shut off power, slide the switch over, and now the loco will be locked in the following mode, which is forward.

Most steam locomotives do not have any on-off switch for the smoke unit. Only some newer locomotives with fan driven smoke units have a separate switch for the smoke unit.

Larry

Glad to hear that your 8601 is running now.

The gear on the armature shaft is part of, and cut into, the armature shaft itself.

The gear and motor setup on that locomotive, and most diesels with vertically mounted motors, will not turn by hand when turning the wheels when fully assembled. Steam locos are manufactured with a different motor/gear setup, so you can turn the wheels by hand.

Use hardware store naphtha to clean off all old grease and oil from the armature, brush holder, gears, wheels, pickup rollers and track.
Replace any worn motor brushes if necessary. Oil both ends of the armature shaft, axle and gear bearings. Add a little grease to the gears, and the loco should run like new.

Larry

The copper section on top of the armature is called a commutator, and is divided into 3 sections for our motors. There are 3 windings on the armature, and one end of each winding gets soldered to its' corresponding commutator section. If you notice one wire not soldered to a commutator section, it must be repaired, or the motor will not run. Most likely the wire gets soldered to the tab on the commutator section visible in the photo.

Larry

What you observe is an insulating material to keep the commutator from shorting out on the steel field pole pieces. Leave it intact.

Larry

Simply unwrap the broken wire one turn from around the winding. The wire will now be too long. Put the wire next to the solder tab and trim to length, leaving it a bit too long. Look at the other 2 windings and just copy what you see.

Larry

Glad to hear that you got the engine to run! Progress!
Sparking from the brushes and commutator is normal. Make sure the commutator, brushes, brush springs and brush holder are all cleaned with naphtha. Worn brushes (very short) should be replaced.

Now to the e-unit.
Some e-units buzz more than others, and there is really nothing that can be done to lessen it. It is just a product of manufacturing tolerances.
Remove the e-unit screw holding it in place, and remove the e-unit. Inspect it carefully. Look at the rotating drum and the 2 sets of contact 'fingers'. If the drum and contacts are dirty, get some plastic compatible spray contact cleaner and spray the contacts and drum. Lift the plunger and pawl by hand to cycle the e-unit manually. Inspect the drum and note the copper contacts on it. Watch how the 'fingers' make contact with the various segments of the drum as it turns. Make sure all the 'fingers' are straight and have proper tension on the drum. Look at the ends of the 'fingers where they contact the drum. Look for dirt, grease, and even holes in them from wear and arcing.

Any problems with either the drum or finger contacts will require dis-assembling of the e-unit for service. Servicing the e-unit is not for the faint of heart and is what separates the men from the boys. It takes a lot of patience and 3 hands to properly reassemble an e-unit.

Here is a 2 part video of an e-unit being serviced to give you an idea of what needs to be done and how to accomplish it. If you are confident in your skills, go ahead and service the unit. If not, a Service Center will repair it for you, or an option is to replace it with a new unit.





Larry

This looks to be the kind of liquid smoke unit your locomotive has.
http://www.traindoctor.com/service/images/8738-200.jpg
The liquid does not crystallize like the pellets do. You may need to add 5 or more drops of smoke fluid if the unit is dry. Look at the left side of the locomotive and make sure the smoke unit piston is being pushed all the way by the drive rod, and returns properly.  Add as many cars as you have to the loco and turn the transformer throttle up to give the smoke unit more voltage. If the smoke is still not puffing properly, the smoke unit may need replacement.
The older smoke units were not fan driven, only the relatively recent units are.

Larry