That mysterious derailing problem! - A story.

[rogertra]

Just thought I'd share this little story.

I'm not one who sends locos back for warranty work unless I'm completely beaten.  So far, in fifty years as a model railroader, I've only done this twice.  First time was when I was fifteen years old and one of my Hornby OO A4 Pacifics died and the second time was August 14th of this year when one of my Alco 2-6-0's right hand main pin broke and I didn't have the tools nor the eyesight to fix it.  So back to Bachmann it went and Bachmann had , 10 days later, fixed and returned the locomotive August 23rd.  

I've been having derail problems with one of my FA-2s over the past few months.  My staging is entered at both ends via an Atlas code 100 wye switch.  Eastbound, as a trailing unit and running in reverse over this switch, I'd have no problems but eastbound as the lead unit, the rear truck would derail on the wye switch.  Strangely, it would have no problems with the western end of the staging yard.  Same switch both ends.  At the eastern entrance, when acting as a lead unit, the front wheels of the trailing truck would lift from the rail, resulting in a derailment and, of course, a short circuit.  

This has been, as you can imagine, a most frustrating problem.  I've checked the alignment of the 36" radius curve leading into the staging yard, I've checked and rechecked the gauge of the Atlas code 100 wye switch at the yard entrance, checked more than once the gauge of the wheels, check the play in the truck, taken off the body to see if any internal wires were getting in the way, etc., etc..  The only difference between the east and west entrances to the staging yard are the east end is entered from the previously mentioned 36" radius curve and the west end is entered from a five foot straight.

Today, I finally figured it out.  Months ago, I'd replaced the coupler retaining cover plate on the rear coupler as I'd dropped the original on the floor and couldn't find it.  So I made a new cover plate and used that in place of the original.  I was checking out and comparing my other FA-2 units to the one with the problem and noticed the stock coupler cover plate on the other units was ever so slightly smaller than the one I'd made.  It was just that much larger the rear end of the rear truck would foul the cover plate when the engine was running nose first.  Out with the flush cutting pliers, snip-snip and the less than one millimetre excess was cut off and BINGO, loco no longer derails.  Ta Da!!!

Entering from the curve must have put just enough pressure on the trailing truck to make it snag the slight overhang of the coupler pocket cover plate while eastbound, entering from the long straight away, it didn't foul.

So, it just goes to show that persistence pays off.

Cheers

Roger T.

[ALCO0001]

Roger,
Thanks for sharing.Great Story!
Jack

[Jerrys HO]

Roger,
Is that persistence or patience.
Like Jack said... Great story.

Jerry

[rogertra]

Thanks guys, glad you enjoyed the little tale.

Cheers

Roger T.