Triplex rear coupler dip

[enginear joe]

I have a MTH Triplex. Recently the rear coupler has been dropping trains. The thing is so strong I swear it could pull a stump out of the ground. The rear coupler mount is the weak spot. It seems that it's too long and unsupported properly. To make things worse, the coupler now joined a few others that have failed. It pops open under load.

 I have upgraded the front coupler to a KD and that is usually how I move long trains with the engine running backwards. So now I'll look at upgrading the rear coupler to a KD also. I think the most important part will be to fix the way that the stock electro coupler hangs out in the air for too long a distance. When I get that mod done, I'm excited to see just how strong this engine really is.

[Jim Miller]

My Triplex rear coupler just ripped off the frame mount. Got a new one from Ray. I'm looking at a way to reinforce it........Jim

 

 

[enginear joe]

Here's what I just came up with. The original was cracked like yours and I forgot that I had added washers to hold it. The new mount area is on the plastic tail piece and is not as sturdy as the original metal place. I had to cut off the back of the coupler box, grind off the tiny tab on the coupler and elongate the holes so they are wider to match the mount. I have a feeling that this new area may need to be supported in the future. I wish it were also made from metal.

[Rayman4449]

Joe, on the coupler dipping I was going to ask if your coupler mount might have been cracked because I have not had problems with the Triplex coupler dipping even pulling 100ft of coal cars up a steep grade.  The mounting point location was chosen to bolt to the die cast metal frame vs the plastic rear deck.  

 

I haven't had a coupler mount break but have seen some like Jim that have.  I'm going to spend some time as well looking to see what can be done to reinforce it.

 

I did pop a protocoupler in the worlds longest train pull attempt back in 2011 as it was seeing forces transfered from the engines/train ahead of it pulling that engine and that engine was pulling forces on the cars+engine behind it's train.  If you're pulling really long trains and are exerting forces that are breaking mechanical couplers then yes I would just go with a Kadee.  It's why I kadee coupler all my rolling stock to begin with.

 

How did you mount the kadee on the Triplex rear plate, did you drill holes in the rear platform or?

[enginear joe]

I elongated the holes wider in the coupler box to line up with the mounts. I used fine thread screws. I felt them slip a little and think they may have stripped? I think it would be better to drill right thru and have bolts with nuts and washers. I am going to look at adding some brass in the form of a U channel to stiffen the whole plastic plate mounting area. It is a weak area and I bet it will fail also if not made stronger. It's only held on by two screws at weak points sticking out of the ends of this mounting plate.

 Those times where trains don't respond correctly or a train gets stretched out too fast for some reason is where I worry. When a pusher or helper doesn't go the correct direction, something has to fail somewhere in the train.

 For someone who has a Triplex and coupler in good condition, I would just suggest some type of support to help from coupler droop under loads. I understand what cars you pulled Ray, and I question whether some like USA's heavier cars (like modern tankers) on grades would make the difference in extra stress?

[Rayman4449]

I was reading that you were having issues and found out you created two different lash-up entries with some engines configured to run in different orientation (ie some engines running in reverse position) and forgetting which one was which causing them to go different directions and thought it was something wrong with the control system or engines.  It may be best to keep notes written down to remember what each lashup is which or just create a new lashup each time you run to prevent future confusion/problems. Also read that you had one TIU with 4.xx and running with remotes with 5.00. Remember, anytime you upgrade DCS versions you ALWAYS upgrade BOTH the TIU AND Remote and if you are mixing TIUs and Remotes then you must do ALL TIUs and ALL Remotes or you are opening yourself up to all kinds of potential problems.  (I dont want to get this thread off topic rehashing other issues being discussed elsewhere but I did want to provide feedback since operational issues were getting mentioned here).

 

On the issue on the screws not tightening down, the immediate issue is you are using the incorrect type of screw (fine threaded).  You need course thread like MTH uses and actually provided with the Triplex but I see another issue here in the fact it looks like you are using much longer screws that go through the Kadee coupler body into the the rear platform posts directly and that is not a good idea.

 

The correct way to do this is to use the MTH provided screws and MTH body-mount coupler adapter plate.  Those screw posts on the bottom plate are meant to hold the provided body mount plate in place.  If you are trying to screw significantly longer screws into those screw posts you are exposing those posts to far greater leverage forces than they were designed to experience and are risking cracking or breaking them.  It is advised to use the parts MTH provided in the manner intended to ensure you dont have problems or break anything. By using the provided coupler mounting plate you eliminate a good portion of the stress on those post screws by the way the plate mates/bonds flush to the bottom of the rear triplex platform.  Then separately bolt/mount the Kadee coupler to the mounting plate.  By doing it this way you end up with a very strong and solid mounting.  

 

Here are the screws MTH provided:

 

 

So for other reading this that are looking to mount a Kadee coupler to the Triplex tender, use the mounting plate and screws that MTH provided specifically for this purpose.  It bolts on solid with no problems, no stripped screws.  Then use a Kadee coupler with a body type like I've used here to allow secure bolting of the coupler body to the MTH mounting plate.  This will avoid/minimize problems installing and the likely risk of problems or breakage down the road.   

 

Also as a note, in the Triplex manual, MTH incorrectly references using a Kadee '829' coupler for mounting on the Triplex. (They also show the mounting of a coupler on the back of a Challenger/Big Boy which I think can lead to some confusion) The Kadee 829 is actually their coupler height gauge, not a specific coupler, so I'm not sure which coupler they were originally saying they recommended using.  What I would do is just use a Kadee coupler with the coupler body I used below to make sure it works and you end up with a strong mounting.  I don't have the coupler number you should use with the correct offset off-hand to provide here now. 

 

Here are some photos of this install on that Triplex:

(This mounting below was done on one of mine so I could have a coupler offset enough to allow me to double-head my triplexes as the front coupler on the rear triplex is high relative to the rear coupler on the leading triplex.  The coupler offset I used is greater than one most people will want to use for coupling to normal rolling stock)

 

 

 

 

 

 

 

Also for others reading this please remember it is important that you use the correct type and size screw if you are going to use screws different than the ones specifically provided and to also be careful you use the right amount of tightening force.  In cases where you are screwing metal screws into plastic you can strip screws out (even with the correct screws) if you exert too much tightening force. 

 

On the 100ft coal train I pull, as I recall one Triplex alone will see wheel slippage pulling that load up my steep grade so it is pulling at it's maximum and using two Triplexes double-headed doubles the maximum force the stock protocoupler mount can potentially see.  So unless you are double heading your train to pull the consist you have I may be seeing greater drawbar pull forces than what you are seeing.  That said I am also going to look at what can be done to reinforce that stock protocoupler mount.  I think what may be happening in some cases is the protocoupler mount screws may be overtightened (as these are screwed into metal) and possibly causing the plastic mount to crack.  

 

Hope this helps some.

[Rayman4449]

Just fixed the photos that weren't displaying.  I deleted them on accident. (hit refresh if you can't see them)

[enginear joe]

Thanks Ray. I do agree with what you post. I have a few differences that could be clarified but don't really need rehashing right now. I found a flaw in the DCS 5.x and MTH is working on it. A quick fix is to press the direction button to get the lashup all running in the correct direction. I only added another older TIU later on. Sorry for any extra confusion.

 I choose a wider boxed coupler on purpose hoping to utilize the holes. I do have the plate shown in a parts bag but didn't use it as those holes did not align with the KD couplers box. I will try long plastic type MTH screws. I feel drilling right thru is nice too. Remember my Triplex is used and abused so I didn't have many stock screws with it. Who broke the coupler mount, I don't know. I'm rambling on and I posted above that I wouldn't!

[Jim Miller]

My fix was to install new piece and added washers to distribute stresses............Jim

 

https://goo.gl/photos/xrDaTciicSaHi2xr5

 

[Rayman4449]

Good idea on the washers, that is exactly what I recommended to another member here as well and will be doing this to mine.