How do you remove the cab from a BLI Mikado?

[Maletrain]

I am working with a guy who is 3D printing the B&O version of steam locomotive cabs, with the extension on the fireman's side to provide a seat for the head end brakeman.  I need to get the OEM cab off my N scale model, but I cannot find a drawing about how it attaches.  I know there is a tab into the boiler at the top center, but the back of the cab seems completely tight, too.

Hints would be appreciated.

Yes, I have detached the wire handrails on the back of the OEM cab.

Update edit: 

OK, I have the cab off.  So, now I can see that there are 2 notches on the bottoms of the rear walls of the cab that fit over bumps on the backs of what look like seats on the floor of the cab, and there are two tabs on the front walls that fit into holes in the boiler, both of which hold the cab down.  There is also a tab with no retaining bumps that is on the front wall of the cab that goes from the cab where it sits along the top of the boiler, into a slot in the boiler. 

I need to drag out my SLR and put a macro lens on it to get good enough pictures to show those things. I will get to that a bit later.

Meanwhile, I would still like to find at least an "exploded" drawing of the parts for this model. Better yet, I would like some directions or a U-tube video reference on how to take the rest of this model apart.  It is not apparent by looking at the assemble condition.  And, I plan to do more work on things like the headlight and the trailing truck.

[Maletrain]

Update: Found the exploded views for
loco:  http://www.broadway-limited2.com/support/N%20Light%20Mikado%20Locomotive%20Expl%20View.pdf
and tender: http://www.broadway-limited2.com/support/N%20Mikado%20Tender%20Expl%20View%20(6.24.2019)%20-%20Copy.pdf

Those were "hiding" in the BLI website on the pull down list "Support" "Support Documents" "Exploded View Diagrams" which are not accessed by first clicking on "N scale Locomotives" in the "Support Documents" list. 

You can just use this link to get to all of BLI's exploded views for every scale and equipment type: https://broadway-limited.com/pages/steam-locomotive-exploded-view-diagrams

But, BLI does not provide any disassembly instructions. Spookshow has some directions on how to remove the shells, which I copy here for others:

"Shell Removal -

"To remove the locomotive shell, first unscrew the two screws underneath the trailing truck and the single screw underneath the pilot truck. Next, pry the shell away from the chassis back by the cab. At this point the shell should lift up and off readily (although it may be necessary to slide the shell forward a little bit in order to clear the PCB on the chassis). Be aware of the wires that run from the PCB to the lightboard inside the smokebox (IE, don't carelessly yoink them from their respective boards).

"The tender shell is held on by simple friction. To free it from the chassis, stick a screwdriver in the opening at the front and pry the shell up and off."

That is all I have found, so far.  None of it would really have helped much with the cab removal, even though I can now recognize the tabs that were giving me trouble when I see them in the exploded drawing.

[spookshow]

It looks to me like it just slides onto the back of the boiler shell. Free up the back-end handrails and you should be able to pry it up and off.

-Mark

[Maletrain]

I did succeed in getting the cab off without doing any damage.

What I found upon getting it off is that there are 5 attachment points, 4 of which have retaining nubs for a snap fit.

There is one tab on the center of the front wall of the cab that fits down into a slot on the top of the boiler, and this is the tab that does not snap in.

There are two more tabs on the front wall of the cab that snap into slots on the sides of the boiler, shaped so that they snap together going downward and lock against going upward.  These are located just above the bottoms of the long windows on the front of the cab.

Finally, there are 2 indentations on the back walls of the cab that are engaged by nubs on the backs of what appear to be "seats" cast on the floor of the cab interior.  Those nubs are shaped to snap together when the cab is pressed downward, and resist upward force.

The way I finally managed to get the cab off was to use a thin blade to pry those rear walls over the locking nubs, so the cab slanted to the front, and then spread/lever the nubs on the front walls out of their slots in the boiler sides, so that the cab lifted off vertically.  Perhaps it would have been easier to pry the front locking tabs out first, but I did not realize they were there.  And I am not sure how I would pry those nubs out without first being able to get under the forward edge of the cab sides by rocking the rear upward - perhaps using the front windows?  The windows are not glazed (yet).

Now that I see now it goes together, I think I can disassemble my other models with much less angst.  The way the cab is attached to the shell might be a little more apparent if the shell is first taken off the mechanism.  I did not do that because I am intending to see how a larger replacement cab works on various track radii. I did manage to get it off without disturbing anything else besides the handrails along the back of the cab.

[bbunge]

...  And, I plan to do more work on things like the headlight and the trailing truck.

Will your headlight work include lifting the headlight to above the boiler?

Following with interest.

Bob

[Maletrain]

Yes, I intend to try to move the headlight to the elevated position the B&O rebuilt most of their locos to, at least until the late 40s, when they started putting them in the center of the smoke box door, again.

But, this will be a learning experience for me, taken at a slow pace when I have time to learn as I go.  So, don't hold your breath for useful pointers from me. 

In fact, I am hoping for some pointers here on TRW, but folks who have already done that. 

Spookshow's photos http://spookshow.net/loco/files/bli282mech1.jpg seem to show that the bottom of the smoke box unscrews, so that should help with access.  And, it is already an LED with a pcb board that connects with a plug.  So, other than lengthening the wire between the headlight and the plug, it might be pretty easy to mount the headlight higher.   But, getting it off the existing location may or may not be easy.  Will I need to destroy it, or can I reuse it?  I have not started to investigate that, yet.

If I have to destroy the existing headlight + mounting bracket casting, I am hoping that somebody will 3D print the casting in clear material so that I can add an 0201 LED and mount  it where I want it on a variety of other models, too.  By painting a clear 3D print, I am hoping to be able to actually have lighted number boards.

But, this is all future project, with no schedule.