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I must admit I was also confused by your use of the term "fouling
point" because I was thinking in model scale track laying. I am
ashamed for not seeing your logic at first because I was also a real time
We always had to be sure spotted cars did not foul the main. The method
was to stand over the rail with one foot on each side and stick out your
arm to be sure it did not touch the car in question.
I have a feeling you were also a railroader do to your reference to the
“beanery”. I worked on the “Snake” Southern Pacific in the San Francisco
area in the 60’s; specifically the Alameda Belt line.
Thanks for your tip on model railroading and be sure to not walk on the
“ball” of the rail.
Headed for the barn,
At 02:20 AM 1/23/2014, you wrote:
In response to my comment:
“ . . . keep those gaps inside the fouling point of your turnouts
and equipment and it will reduce the number of problems due to shorts by
reducing the possibility of shorts.”,
“Are you suggesting gaps closer to or farther from the frog? Could
you explain what you mean with a little more detail? Or point us to a
diagram or discussion.>>
I’d be glad to, Bob.
The Fouling point is the location where equipment on the diverging tracks
of a turnout would sideswipe each other. Trains & equipment
need to be spotted beyond the fouling point so equipment can move
into/out of the adjacent track without sideswiping each other.
Starting from the point end of a turn out, you have points, frog, fouling
point. Your gaps go between the frog and the fouling point.
These gaps should be as close to the frog as is reasonably possible given
the track construction methods used.
The rationale is this – In theory, (most, there are always exceptions
<>) operators will keep equipment beyond the fouling
point so trains don’t snag on each other. If they do that (as they
should), and the gaps are between the frog and the fouling point, the
metal wheels of stopped equipment are unlikely to span the gap,
potentially creating a short if the turnout is thrown against the
equipment spanning that gap.
We had an incident on a local layout where this actually occurred.
Track was hand laid, and one side of the frog extended about six inches
down the yard track. A train entered the track from the far end of
the yard and pulled down to the far end, where it stopped with one of its
front wheels spanning the frog gap. As the engineer was moving
slow, he was almost stopped when tht axle spanned that gap, and didn’t
notice that he’d straddled the gap. The turnout was against him, so
the frog was one polarity and the rail under the train the
opposite. Additionally this was the last train of the
session, so the short went completely un-noticed. The layout was
shut down and we went to beans. Several work sessions passed where
we had track power on for various reasons. When we finally went to
move the train for re-staging purposes, it wouldn’t move.
Inspection revealed that the gear on the front axle had gotten so hot
that the plastic had flowed around the bearing block on that side of the
axle, and had cooled around the bearing block effectively freezing the
mechanism. Layout owner, not realizing that any of this had
happened, attempted to move the train by turning up speed on
throttle. Only thing that happened is track to decoder and decoder
to motor wiring got hot and the insulation burned off.
All of this would have been avoided if the gaps had placed properly
(between the frog and the fouling point originally.