Fixing the Army Missile Launcher locomotive - any experience/hints?

I have one of these - the 6-28411 PWC series version from about 2006. Before I open it up to try and solve what I think is a frequent operating issue, I thought I'd ask whether anyone has any experience of fixing this.

The problem is that triggering the remote firing mechanism from a CAB 1 or 2 usually results in at least one of the four missiles not launching. It is usually the first one triggered by the mechanism illustrated below. Sometimes more than one will not launch and I have noticed that to work properly at all it has to be positioned near a power feed to the track. As a result, in my CAB2 this engine is named "MISFIRE."

I have the Army missile sounds boxcar too and the  set as a whole is a crowd-pleaser although when it mis-functions you can imagine the joke's on me.  

I have looked at the remote mechanism and shown below are what appear to be the main components; essentially I think the coil triggers the plunger (top right) in what I think is much the same way a coil coupler works and the plunger pushes the plastic camshaft (top left) a quarter revolution, which is supposed to release each of the spring-loaded launchers in turn. 

RemoteFiringComponents

The launcher is a separate assembly and a view of one from the bottom is below; I have not figured out yet exactly what in this the camshaft engages but it must be part of each trigger once pulled back to compress the spring:

Launcher

This appears to be exactly the mechanism used in the original postwar version of this loco, #44, but with a TMCC control board to trigger it.  I haven't actually found a parts diagram for these components apart from this dating from about 1960:

loc44p1

A while back there was a thread on these engines and mention made in it (by GRJ) of filing down some of the parts to get reliable operation, but I don't know if that related to the same problem: https://ogrforum.ogaugerr.com/...63#40426816890624363

Final piece of info: using the trigger plunger manually results in each missile firing correctly. Coupled with the need to keep the engine on or very near the track power inputs suggests to me that the coil/plunger lacks enough oomph to move the first trigger. Anyway how to remedy this annoying defect is a puzzle to me. 

BTW, I think that Lionel must have dropped the version of this loco catalogued in 2015, which is the main subject of the linked thread. I can't find that model (6-81545) listed anywhere and maybe they could not adapt the old firing mechanism to Legacy control or decided not to?

Attachments

Photos (3)
Original Post

I have rebuilt many of the original Postwar units. I haven't done any of the reissues, but am somewhat familiar with the construction of the launch mech.

The typical problem with the postwar versions is multiple rockets firing together, which is caused by the foam under the mechanism decaying.

Sounds like the coil isn't pulling in the armature/pawl that rotates the firing cam shaft. Someone else mentioned the problem in the thread you linked. The Postwar one needs a fair amount of power to fire reliably. I've always used fixed voltage to test end  operate mine. 

There are no Postwar Lionel diagrams for the #44 / #45 missile locos. I think Lionel did something for the modern era ones.

C.W. Burfle

What voltage is your transformer set at when running TMCC? Not enough voltage to the track?  The coil does take some power to operate reliably. When a missile doesn't launch, did the firing mechanism trip? Is the foam pad original and not too hard? When you launch in TMCC is the mechanism responding? Can you post a short video of it in operation so we can see what is happening?

The problems I have found is the shock of launching one sometimes will bounce the next missile off it launching cradle. The newer TMCC versions have weak launching springs and just 'dribble' the missile a few inches in front of the launcher. I took the launching mechanism apart and used the springs from a junked postwar 6544 missile firing car. Now it launches the 'Little John' missiles into enemy territory and explode the hidden ammunition bunker! 

Chuck Sartor posted:

What voltage is your transformer set at when running TMCC? Not enough voltage to the track?  The coil does take some power to operate reliably. When a missile doesn't launch, did the firing mechanism trip? Is the foam pad original and not too hard? When you launch in TMCC is the mechanism responding? Can you post a short video of it in operation so we can see what is happening?

The problems I have found is the shock of launching one sometimes will bounce the next missile off it launching cradle. The newer TMCC versions have weak launching springs and just 'dribble' the missile a few inches in front of the launcher. I took the launching mechanism apart and used the springs from a junked postwar 6544 missile firing car. Now it launches the 'Little John' missiles into enemy territory and explode the hidden ammunition bunker! 

Thanks very much for your helpful responses and answering Chuck's specific questions the position is as follows:

1.  It's a fixed command voltage of 18 volts. In case it matters, when I last ran this engine I had an MTH Z4000 but I have since gone over to a ZW-L because of what I had learned about Lionel/3rd Rail smoke units and sine waves. The voltmeters on both transformers have always registered at the highest end of the output range although when I measure it on the track with what I believe to be an accurate meter (I have tried more than one), it consistently comes out at more like 16 VAC. The track and power terminals are K-Line/RMT Super Snap although I used Atlas before.

2.  Yeah, I can hear the firing mechanism engage (coil energizes and the plunger moves) each time I use the F (fire) command but on the first launcher it does not seem to trip whatever mechanism releases the spring. The second time I use the F command the next missile will fire and usually the other two in sequence as well but not always. This made me wonder whether the camshaft was engaging correctly. I did not know that the plunger pulls on it rather than pushes.

3.  I never thought of checking the foam pad but then I forgot that it is meant to hold the various triggers in place. I'll have a look at that. It is original equipment. 

4.  Of course the only video I have saved of this unit in operation is one where it worked as it should (and blasted a special target representing two public figures I don't like)! I had it sitting right on the track with the power inputs. I'll see if I can get another one later in the week.

Thanks again.

I had to take mine apart and clean up all the actuating surfaces and "tune" the latching until they'd fire reliably and not fire two or three at a time.  Now I have it about 99%, maybe once in 20-25 times it may mis-fire or do a double-fire.

I never thought of checking the foam pad but then I forgot that it is meant to hold the various triggers in place. I'll have a look at that. It is original equipment.

The foam pad does more than hold things in place. It applies pressure to the locking mechanism.
On the last rebuild I did, I found it to be beneficial to slit the foam pad between the individual latches, so when the foam was compressed by one latch releasing, it didn't compress the foam under the next latch.

As I write this, I am wondering whether the foam pads that Lionel used on the reissues is too stiff. But if that was the case, the plunger wouldn't be able to pull in all the way, and rotate the cam shaft at lower voltages. 
On the postwar version, the pivot pin for the pawl sticks out of the body for manual firing. You can watch it to see if the solenoid is pulling the armature in all the way.

C.W. Burfle

Well, I can't say I have had the problem of more than one missile firing at once or of one being bounced out of position by another one firing. (Probably should count myself lucky.) But I'll test it with the ZW-L this week and see how it performs - before I start taking it apart. I have had it apart once but could not see any readily user-servicable parts, especially in what I now know to call the solenoid that triggers the camshaft. 

I think the hardest part of working on these engines is removing and replacing the shell without damaging it.
The front of the frame has slots that are inserted into slots in the shell, right where the bumper begins. Move the frame the wrong way, and the bumper gets broken off.
It's also a tight fit to get the shell over the launch mechanism.

As far as slicing the foam goes: cutting slits should also reduce the pressure to be overcome when the cam is trying to trip the mechanism. Trouble with this technique is if you mess up the slits, you need a new piece of foam.
I use foam window weather stripping to make my own foam. I guess that replacements are available from Lionel or Lionel parts dealers these days. But for many years folks had to make their own.

C.W. Burfle

Well, guess what? I put this engine on a track powered by the ZW-L and the firing mechanism consistently works without a hitch. The amp meter on the transformer jumps up to about 1 amp when the firing coil is energized but I can't see that's excessive. Admittedly the track is an isolated section with power from the A-U terminals but it's several feet long. I think that this narrows down the issue to the power necessary to get the mechanism to trigger and I don't think I have anything to gain by opening up the engine to try to fine tune the mechanism. I can create a siding when I want to "launch" an assault on some target for the benefit of my visitors.

The engine still runs like a dog with no real slow speed control and it derails all too easily. But I guess with the Pullmor motor and the mounting of it on the front truck that's just the nature of the beast.

Thanks again to everyone who responded.

Add Reply

Likes (0)


OGR Publishing, Inc. PO Box 218, Hilliard, OH 43026 330-757-3020
www.ogaugerr.com
×
×
×
×
×