Different Length Brushes?

If the brush wasn't contacting the armature, the locomotive will go nowhere, hence "stuck in neutral".   I'm not saying that's the only problem, but it certainly is something you should fix.

Because this engine/chassis has no real "number" is there a generic brush to buy?

Because of the size of the brushes I would recommend replacing them. But first clean the brushes up with a pencil eraser and make sure the brushes have good contact pressure against the armature and also that the armature is clean of dirt.

Take the brushes to a Lionel parts person and he/she should be able to match you up with a set of brushes. Don't go to an electric motor supply place as they deal with large horsepowered motors only and won't have what you need, I tried that one time.

Lee F.

The brush length seems good to me.  The fact that one is longer than the other may be because a prior owner only replaced one brush.  If the brush springs are good, I suspect your problem is in either faulty/dirty e-unit contacts, dirty drum, dirty armature or dirty brush tubes.

Earl

Without more info it would be hard to say what brush you need. The F 3's used at least 2 different types. Did your brushes have springs on the back, or were they just plain brushes? There were horizontal motors and vertical motors. Don't even bother cleaning brushes. Toss them and get new ones. Clean the brush tubes well also. The E unit can appear to cycle correctly but still not work. You probably have bad, or very corroded fingers or drum in the E unit and that likely was your biggest problem. What is the cab number at the front?

Rob

As far as I know, two different style brushes were used.

Early motor used this:

If the brushes have coil springs behind them to press them against the commutator, then the brushes are 2020M-33, with spring 2020M-34.

Most motors used this:

If the brushes have hair springs mounted in the brush holder to press them against the commutator then the brushes are 622-121, with springs 622-191