Coupler Trip Pins on Passenger Cars

[CBQ Fan]

It seems that almost every passenger car I bought lately (you name the company and I have had this happen to at least a couple) have had trip pins that are so low they catch in almost every turnout.  Now I run code 80 and while a little annoyed I fix them.  I never have looked into code 55 because I have so much code 80 available and I would rather spend the money on rolling stock, but I have to wonder wouldn't this issue be worse for code 55 than on code 80?  Mine have been so bad I would think with lower profile rails that they would bottom out even on flat straight sections of track.  I really like how Kato leaves you the option of putting them in if you use them or like them. 

[Zox]

I wouldn't think that rail height, in and of itself, would make any difference. After all, the distance from the bottom of the trip pin to the top of the rail isn't affected by rail height. Either the pin clears, or it doesn't.

[CBQ Fan]

Maybe I am thinking of it wrong but if the bottom of the pin is X amount below the plane of the bottom of the wheels (and therefore the top of the rail) than having a lower rail height would cause the bottom of the pin to be closer to the top of the ties, possibly hitting the ties.  Mine have only been hanging up on the frogs and switch points.

[SP-Wolf]

The rail code has nothing to do with it. As the wheels and trip pin are/should be above the rail. If the pins are to low- they would be to low regardless of the rail code. About the only thing the rail code affects is the wheel flange depth. Pizza cutters don't like code 55 and smaller. As a general rule.

Wolf

[PAL_Houston]

Just because we're coming up on the weekend, and need something to re-hash ( ):

1.  The quality control on couplers coming from the factory ought to include checking the trip-pin height so we don't have to bend or remove the little @#$%'s to make them run right!

2. Nobody uses magnetic uncoupling anyway!  (This ought to raise some responses, if nothing else does!!)

3. The least they could do is blacken them, so they wouldn't stand out so much!

4. blah. blah. blah. 

[peteski]

Magnetic uncoupling is cool! 

Brian,
if the trip pins snag on the track that has nothing to to with the height of the rails!  They will snag anytime they hang down any lower than the *TOP* of the rail (rail head).  If it snags on code 80, it will snag on code 70 or 55 or 40 or 20 and vice-versa.

All you need to do is either push the pin a bit higher into the coupler or curve it up a bit by bending it with pliers (you can even buy special pliers made specifically for bending the trip pins).  MicroTrains used to (and probably still does) sell a trip pin clearance gauge. It is basically 0.010" thick piece of stainless steel. 0.010" is the MT recommended coupler clearance over the top of the rails.

[Chris333]

I cut the pins off everything I own. I hate when I pick up a car and the next one comes with it.

[davefoxx]

I cut the pins off everything I own. I hate when I pick up a car and the next one comes with it.

Me, too.

[CBQ Fan]

Peteski & Dave, I may just have to do the same thing and pull them out.  I have bent quite a number up.  Having never held or used code 55 I just had this mental image of the pin dragging along down the ties of a straight tangent of track, going thump, thump, thump, thump!!   

[Kisatchie]

Peteski & Dave, I may just have to do the same thing and pull them out....

Don't pull the Micro-Trains pins out. You can cut the lower portion off, but the upper part holds the coupler together so it doesn't come apart side to side.


Hmm... model railroading
is so technical...

[nkalanaga]

CBQ Fan:  You're right that rail height matters of the pins are snagging on the ties.  However, they will snag equally well on turnouts and crossings regardless of the rail size.  If they're low enough to hit the ties the coupler itself is probably too low.

And, as Kisatchie says, don't pull the pins out, cut them off.  The couplers work better with the stub left in, and you're less like to bend the coupler shank if you don't pull on the pin.

[peteski]

Peteski & Dave, I may just have to do the same thing and pull them out.  I have bent quite a number up.  Having never held or used code 55 I just had this mental image of the pin dragging along down the ties of a straight tangent of track, going thump, thump, thump, thump!!   

Brian,
something about your problem just doesn't add up to me.  Here is my experience.  I show a standard MT freight truck but passenger trucks with truck-mounted couplers have similar construction.  I'm assuming that your cars do not have body-mounted couplers but even then the trip-pin height would still be adjusted the same way and would still need to be clear of the top of the rails just as with truck-mounted couplers.



Example A shows the trip pin which is correctly adjusted compared (on the left) and the MT coupler height gauge (on the right).  MT recommends 0.010" space between the bottom of the trip pin and the top of the rail (regardless of the rail code since the wheels always ride on the top of the rail).  In this example the distance between the rail top and trip pin bottom is more like 0.020" becasue I like some extra clearance, just in case...  Couple in this photo will not snag on any trackwork or on any road crossing the rails (as long as the piece between the rails does not protrude above the rail height).

Example B shows a trip pin that is too low. As it is clearly visible, it is slightly below the rail top and it will snag on every turnout, crossing or road crossing the tracks.  The truck I used is the same as in example A but I simply pushed the trip pin down from the top. You can see that by looking at how much of the trip pin sticks out over the top of the coupler in example A comparing it to example B.

I pushed the trip pin as low as it could safely be pushed down. Unless I bent the trip pin down severely, there is no way I could get it ever to snag against the ties (even on code 55 track). The rail in all these photos is Kato Unitrack code 80.

Example C shows one way of raising the trip pin height.  You simply have to push the trip in up through the coupler (see the blue arrow). Compare that to how much of the trip pin sticks up in Examples A and B.  The truck in this photo is the same as in the above examples but  purposely bent the trip pin down to demonstrate this method of adjusting the trip pin to the proper height.

Example D shows the other method of adjusting the trip pin. You simply bend it up. In this photo I slightly exagerrated the bend and the trip pin sits a bit higher than the pin in my reference coupler on the right.

As others have mentioned, if you want to get rid of the trip pins on MT couplers, do not fully remove them (which would make the coupler unstable), but just cut off the bottom curved part.  Same applies to McHenry couplers. With other brands of couplers (like Kato or Accumate) you should be able to fully remove the pin.

But going back to your problem, I cannot understand why you are unable to adjust the pin height (or bend it up) high enough to clear the rail height.  Have you looked at your cars from the same angle I took the above photos?  Do the trip pins clear the rail tops just like in example A?  If they do have plenty of clearance, have you observed your problem cars slowly traversing the turnouts to see how exactly
they snag on the turnouts?

Do you have on of the MT gauges I used in those photos? It comes in very handy for checking couplers on your cars.


Nkalanga, Look at my photos.  The rail height (code) does not matter in this problem since the trip pin will *ALWAYS* snag on the rail from the top, no matter how much it protrudes below the rail height and will *FIRST* catch on the crossing rails while going through turnouts and crossings, way before it it would have a chance of ever contacting the ties.

[nkalanaga]

Peteski:  I agree.  The only way to snag on the TIES while running is if the track has nothing but plain track, as turnouts, crossings, and any other obstructions will catch the pin first.  But in CBQ's second post he mentioned hitting ties, which would depend on the rail height.  If it seems to be snagging on the ties, it could also be hitting track nails, if the track is laid with nails.  He also says his problems are at frogs and points, where you're right, rail size doesn't matter.

Another factor can be pushing cars.  A coupler that is at the proper height by itself, or pulling, can droop when being pushed, snagging on turnouts.  Those can be especially hard to find, as they only snag when they are pushing against another car.  Being pushed, the pin is trailing, and can slide over the obstruction, and on the workbench, they look good.

[CBQ Fan]

I have typically just been bending them up and out of the way.  The thought just crossed my mine that with the focus on code 55 friendly rolling stock that the quality control would keep the pins at a much closer tolerance. 

I have run into example B more often than not when I have run into issues, and I do C or D to resolve.  Great photos!!  Thanks.

Overall it is a small percentage of cars that have the issue but the percentage is spread out over several makers.  From my perspective it is a very minor annoyance when I have to tune the couplers right out of the box just to get it to roll over track, but from what I have heard and read about C55 it seems to require tighter tolerances to work smoothly.

[peteski]

From my perspective it is a very minor annoyance when I have to tune the couplers right out of the box just to get it to roll over track, but from what I have heard and read about C55 it seems to require tighter tolerances to work smoothly.

Doug,
code 55 track is no different when when compared to code 40 or 70 or 80 while trip pins are concerned or even when wheel tracking is concerned. Think about it, both are directly related to the top of the rail.

Wheels roll on the top of the rail (with the flange rolling on the inside edge of the rails. Coupler trip pin must be certain height above the top of the rail in order not to snag on track work or on road crossings.  The height of the rail has no bearing on how well the train will run (the tolerances you speak of would be the same for C55 the C80).  The photos I took would have shown the same exact scenario if they were taken on a piece of code 55 or code 40 track.  Again, it is the top of the rail (not its heigth) that makes all the difference here.

It seems that you got stuck on buzzwords like (higher tolerances on code 55 track). The thing that makes a difference on finer track like code 55 or lower is the wheel flange height (as the flange extends below rail height and if the flange is too deep, it will actually hit the ties or spikes).

I think that the tighter tolerances you speak of are the clearances of the frogs and guide rails.  Most N scale code 80 uses dimensions designed for toy trains back in the 1960s.  Code 80 track's  flangeways are quite wide.  Those specs are looser than NMRA recommendations. However many (but not all) code 55 track manufacturers adopted the NMRA specs. So their flangeways are tighter.  This makes their track be more sensitive to the model's wheels being in gauge and to the overall shape of the wheel profile. But it does not make it in any way be more sensitive to height of the trip pin couples.

As far as the annoyance of the trip pins not being properly adjusted, my experience is similar to yours (I have to adjust some of them on models fresh from the factory). I really don't think that model manufacturers even considered improving their trip pin adjustment tolerances just because there is now finer track available out there. Again, because the trip pin operation is not affected by the height of the rail.