Western Railroad Discussion > Hump yards -- are the bowl tracks level?

What's the best design for a hump yard --
the bowl tracks are dead level, or very
slightly downhill, 0.1% say? If they are
downhill, do they always ramp up at the end?
How much downgrade is too much?

SP built humps at Roseville circa 1907, east
of Dry Creek, which meant the cars had to
run over the hump westward -- eastward was
0.4% upgrade. Bowl tracks are never upgrade
at all?

(Presumably when the hump moved west of Dry Creek,
eastward was no longer upgrade, so they could
hump eastward.)

There's a reason it's calld a "bowl." .

I worked the Milwaukee Bensenville Yard at night, 70 tracks, each shift there was a low side and high side skate man and we had a shanty and speaker.

Every track had to be skated( a metal rail like a portable bumper that the wheel would roll up on .  The skate would slide(skate) along but the additonal friction would slow down the cut.
Generally if could find two skates I would put a skate on each rail offset since some times a skate would be knocked off.  Often we would shim the skate with a wood chip to improve the chance the car would ride up the skate.

The yardmaster might give us a heads up over the intercomm wehn the first cut would come down so we could watch it.  As I remember we would often set a handbrake on the first one or two cars.  The yardmaster would also call somewhat frantic if a cut got away from the retarders, you would make your way over to the track and get on setting a hand brake. I remember having to set it on two cars to get the cut under control.

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Now to the grade, whatever up grade there might have been on the end away from the hump it could not have been very much, it was not assumed enough  to slow down the cut of cars and you certainly didn't want cars rolling back toward the hump and you wanted them to roll down within a reasonable distance.

On the hump side I assume a small down grade but flattening out. Youd didn't want a cut hanging up close to the hump so the crew had trim the yard but obviously you also didn't want them picking up speed if there was an extended down hill.

Obviously you want to avoid a rollout on the ladder tracks.  I know yardmaster on the downside end was watching cars and if a cut got too close he would send a crew to push them backup.

Pulling a track the first thing was to find any skates which would not always be on the first car since cars could be pushed in from the low end of they yard then watching for any hand brakes.

Bob Jordan

I added a photo for reference, I can tell you none at Bensenville were light weight or looked anything like this.  they all looked original from 1947 or whenever the hump was installed.



Edited 2 time(s). Last edit at 04/16/21 09:07 by robj.

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This is a skate.

-LD

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LarryDoyle Wrote:
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> This is a skate.
>
> -LD

Thanks, that is more like the ones we had, only beat it up have a hundred cars run up on it.

Bob

I think a little downhill is OK, but the force added to the moving car by the grade would need to be less than the rolling resistance of the car. You do not want a car to accelerate after it leaves the last retarder, though sometimes wind could cause that.

In humps in colder climates, early hump yards handling friction bearing cars would have bowl track grades in the realm of .15 to .25 % (!!).  Now that cars are roller bearing-and even those are improving over time-I think the overall standard is about .08-.10 of one percent descending in a tangent bowl track. The 'up-grade' on the trim end would be steep, visually so-the idea being to get cars rolling away from the hump to gather up as near the trim end as possible without running out. Having the right balance at the end of the track between speed and distance is a fine line, and so you the apt comments on skates above. You might have instead some form of activated or uncontrolled 'inert' retarder. In severe cases, some carriers have used 'post cars' at the end of each track (i.e., leaving two behind when ever you pull the track out) to assure subsequent cars don't run out. Post cars are sort of last ditch, IMHO. They can cause a lot of switching if your bowl track/block assignments shift around (they do), or 'lost' cars/ inaccurate lists.

The other kettles of fish are the grades associated with the track from the crest to the tangent point of each track, the arrangement of the turnouts getting there, and the quality of your control system.  Lots of variables in each case. 

The hump in Eugene (SP) was pretty sophisticated when built. It had a scale on the bowl side of the hump to weigh each car and it would calculate the exit speed from the retarders to make it into the bowl safely. There was also a retarder operator who could override the system and regulate the speed. The tracks themselves were very slightly downhill away from the hump simply because that was the lay of the land. At the far end of each bowl track, 32 tracks, they had inert retarders that would catch cars so they wouldn't come out of the track. They worked pretty well assuming a car wasn't coming excessively fast. In time they became less effective due to wear and cars getting heavier so it became standard to leave a single car with a brake in each track as the trim engines built trains, which worked pretty well. This was a nuisance though having to stop and cut a single car off every time you pulled a track so they added a job at the east end of the bowl as a "skate herder" whose job was to place skates on tracks as the trim engines cleared the tracks. He would also catch the first car into the track and leave a brake on it dropping the skate once a car was secured. 

As a note, the skates had their issues as it was not uncommon for a loaded car to come into the track too fast and the leading wheel would go over the skate causing it to get jammed under the truck of the car. It was always fun having the car department come out with cutting torches usually to extricate the skate from under the frame of the truck. 



Edited 1 time(s). Last edit at 04/16/21 12:27 by Railbaron.

Here's a sketch of a hump yard, with profile, from John Armstrongs' The Railroad, What It Is, What It Does.

Note that the bowl tracks are marked "Less Than 0.25%".

-LD

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boxcar1954 Wrote:
-------------------------------------------------------
> .... In
> severe cases, some carriers have used 'post cars'
> at the end of each track (i.e., leaving two behind
> when ever you pull the track out) to assure
> subsequent cars don't run out. Post cars are sort
> of last ditch, IMHO. They can cause a lot of
> switching if your bowl track/block assignments
> shift around (they do), or 'lost' cars/ inaccurate
> lists.

Thanks for your comments, boxcar1954.

Post cars could lead to some creative lying for a service guy.  How do you tell a customer that his car which you assured him was going to depart on a particular train would be at the yard for another day? You certainly did not want to tell him that is was being used as a bumping post.

Here in Chile,  when a unit is tied down,  even in an engine terminal, there is always a skate under a wheel of each truck.  They're placed the minute the unit is stopped and/or shut down.

Since we are more into this, a followup on Bensenville.
The hump yardmaster was in a tower at the crest of the hump.  The conductor in the tower under the yardmaster. Luckily only a few times for me as my time I was new.
Conductor would have car list.  There was a panel of buttons for the tracks and the conductor would call out the cut size for guys outside.  If they were auto racks you really had to hustle back to get the pin before the cars started pullng out the slack.  We had 4 man crew but can't remember if head brakeman stayed with engine or was wth rear end guy making the  the cuts.
There was low and high side retarder operator in their own towers.

The hump crew would tie onto a cut on an inbound track, the cut would head west, there was a switch tender to get him out of  yard.  Conductor and switchman would then walk over to the hup.
They were pretty long cuts and the head end would go out on a stub track almost in Bensenille by the station.  There were color position lights to control movement can remember if conductor controlled movement, probably did.

After a cut you might go down into the yard and trim some tracks.  The car department was off the hump reached by track 00 and I think sometimes you might go over there.

Hump was probably least desirable job for most  unless you were at the bottom and wanted to try hold a job for steady.  If you were on the extra board and hoping for some cool afternoon job in the city the last thing you wanted to hear....

The tug of war was at the end of the shift where you fought with yardmaster for 15min ot or quit, this is when a city job could get you a 2 hor quit or transfer 14 hours.

The job I hated most was the afternoon pullbacks.  the guys with lke 10 years held these jobs, often a second job, work maybe for city during the day. After doing little during the day they would make you do all the work so they could do very little again except make jokes at your expense.

New guys were great, we watched out for each other, the old guys were even better, many of 10-15 year guys, one reason I moved on.

Bob

 



Edited 2 time(s). Last edit at 04/16/21 13:19 by robj.

I did work Eugene for a couple years. The inerts must have been pretty good then as I recall little trouble with run outs. More recently, in other yards, inerts, while still good if maintained, had issues. The weight is a big part of it, but also inerts as designed earlier when most were installed (and generally not upgraded) were 39 feet overall, and a shorter surface than that with the retarder shoe. This meant the predominant 40' car would for a time get both trucks (all eight wheels) in the inert at the same time, which helped.  Most cars these days have truck centers well past that, so in addition to being heavier they only have one truck in the inert at a time....

A well maintained inert is a good tool. Stopping power does degrade very slightly for every wheel set that goes through. Maintenance is key--something most carriers like to, shall we say, minimize.