LIONEL 3454, solenoid ?

[cwburfle]

I place a 3/16 or 1/4 inch flat bladed screwdriver in the track, right next to the end I want to remove.
Apply gentle pressure while heated the head of the pin. Once the pin lifts a bit, stop applying pressure, and remove the heat. The head will stick up so it can be grabbed with a pair of diagonal cutters, and gently pulled out. 

To clarify: I twist the screwdriver, so the edge by the pin is trying to lift up the door guide. I also place an index or business card between the screwdriver blade and the car body to protect it.

[TRACTORSNTRAINS]

Fear the problem is not the door. I have the problem even when the shell/ box is not connected to the frame, with the little piece of wire completely disconnected from its door pin.

[gunrunnerjohn]

I have two of those cars, and the doors are virtually always the problem you describe.  It takes some tinkering to get them working, then you don't ever take the shell off again!

[cwburfle]

Powered graphite will stain your car.

As you implied in your post, the cause is likely to be the door dragging in it's tracks.
If the car came to me for service, I'd probably remove the door guides.
Then I would make certain they were nice and clean / rust free on both sides.
If the guides are not nice and straight / smooth, I'd replace them.

Next, I would make certain that the doors were also nice and clean.

I don't think I would use any lubricant at all. If I did it would be something slippery that is clear, and doesn't stain. (Too bad they don't make clear dri-slide any longer)

Then reassemble, makeing certain the door guides were not put on too tightly.

Tip: the pins that hold the door guides in place can be removed easily if they are heated a bit with the tip of a soldering iron.
Make certain the tip is clean, you don't want solder dripping onto your car. (I have a tip set aside that has never been used for soldering).
Don't overheat the pin, you don't want to melt or burn anything..
I place a 3/16 or 1/4 inch flat bladed screwdriver in the track, right next to the end I want to remove.
Apply gentle pressure while heated the head of the pin. Once the pin lifts a bit, stop applying pressure, and remove the heat. The head will stick up so it can be grabbed with a pair of diagonal cutters, and gently pulled out. 

Sometimes it is also helpful to heat the head of the pin when re-installing it too.
I place the pin in the hole as far as it will go with little to no pressure. Then I push it in the rest of the way by placing the hot soldering tip on the head, and gently pushing down.

I notice that I used the word gentle many times in this description, I guess it must be an important point.
I've had lots or practice doing this. When trying something new, I recommend practicing on a junker.

[TRACTORSNTRAINS]

I know the 3454 is a temperamental old car, but I am going to hazard asking help improving operation of the one I have. The solenoid retracts fine, but the only what for the solenoid to un contract is to take the car apart, and push the rod forward. Would powdered graphite along the side grooves help?

Also, some times the couplings open when I press unload, and some times they uncouple when I press uncouple.

Thanks