The Transcontinental PRR

[wm3798]

You realize you're going to need a staff of 35 people to run this layout, right?  Better have a lot of couches in the crew lounge!
Lee

[Bob Bufkin]

And a large beer frig.

[eric220]

Beer fridge taken care of. As for the number of operators, I need somewhere to put guests! 

[MichaelWinicki]

They still go over the hump just the same lol.

You may have a point...

I talked to an engineer who started out on the PRR in 1955, and operated out of the Olean Yard, which was still a functioning hump yard and here is his reply to my question on which cars weren't being shoved over the hump in Olean in that time frame...

"The cars that couldn't go over the hump were extra long deep center cars where the trucks were articulated so the ends could turn separately, they had to be taken somewhere that had bigggg scales to handle that type car."

[Philip H]

I seem to recall an article about using air jets as retarders in a scale hump yard. Not sure where I saw it or how it would be accomplished.

MR in the early 1980's - it was a guy in HO doing one of the ATSF yards in the midwest.  Almost makes me want to dvd set . . . almost . . . .

[Bob Bufkin]

There was a working hump yard at the last N convention held at Chantilly years ago.  I never aske about retarders but it was way cool watching cars come down the hump to different tracks.

[eric220]

They still go over the hump just the same lol.

Actually, question about that.  Would the prototype just tow them over the hump with a locomotive?  In my case, "do not hump" cars will be mechanically unable to go over the hump.

[davefoxx]

Actually, question about that.  Would the prototype just tow them over the hump with a locomotive?  In my case, "do not hump" cars will be mechanically unable to go over the hump.

I think, on the prototype, they're switched around the hump for the same reason.  Think about how certain cars like depressed center flat cars, which would likely be unable to physically circumnavigate the hump without problems, as well as cars with special loads that might shift on the severe angle/grades on the hump.

DFF

[MichaelWinicki]

I think, on the prototype, they're switched around the hump for the same reason.  Think about how certain cars like depressed center flat cars, which would likely be unable to physically circumnavigate the hump without problems, as well as cars with special loads that might shift on the severe angle/grades on the hump.

DFF

You pretty much nailed it Dave.

Here in Olean there was no hump yard/flat yard differentiation.  If a car couldn't go over the hump then it was switched into the other end of the yard via the flat end. 

I think the folks that designed and built the yards for the PRR would need to have some pretty good reasons for wanting to build a dual yard where several classification tracks were not accessed via the hump. 

Our two hump yards were started in 1905 and were expanded until the mid-20's and even then they didn't add any trackage that was somehow not connected to one of the two humps.  Again if the car couldn't be humped then it was pulled around the hump yard to the flat end and thusly classified.

[eric220]

Again if the car couldn't be humped then it was pulled around the hump yard to the flat end and thusly classified.

Ah-ha! I was wondering if that was the case.  So really all that's needed is a runaround, and the bowl end can be switched like a flat yard.

[Bsklarski]

We see some box cars with paper rolls come through with tags that say DO NOT HUMP, but I know for a fact they get humped as they are in the middle of blocks that come from the same place/train and get sent over as blocks. As for mechanical reasons, yes no way you can hump a 87' depress center flat car or something like that. Also perhaps PIH cars? Humping is almost the same as gravity drops. Not sure about that lol.

[MichaelWinicki]

Ah-ha! I was wondering if that was the case.  So really all that's needed is a runaround, and the bowl end can be switched like a flat yard.

Exactly!

[eric220]

After some messing around with the last round of advice and moving the mains back together past the classification yard, I came up with this:



The green tracks are the mains. 8 classification tracks, shortest track is 37" long, longest is 91" long.  The small flat yard in the front is an interchange yard with the coal mine branch.  I was also able to tuck the MOW track in next to the bowl instead of its old location off of the main behind the A/D yard.

[davefoxx]

Obviously, I'm speculating here, but I'm concerned that your class tracks are too short, once you factor the grade into them.  In other words, by the time the track levels out through the ladder and retarders, there's not likely going to be much left, especially in the shortest class tracks.  Can you shift the hump towards the left in your plan and extend the class tracks?  You may want to mock this up to determine the run/rise on each side of the hump.

By the way, if it were me, I would want to see class tracks that had more similar lengths.  Obviously, they don't all have to be exactly the same, but I think the simple ladder at the far end is killing the capacity of the yard.  There's got to be a better way.

DFF

P.S.  Although I'm red-green colorblind, I can distinguish the green tracks in your recent plan.  Thanks!

[eric220]

P.S.  Although I'm red-green colorblind, I can distinguish the green tracks in your recent plan.  Thanks!

'Welcome!  I'm at the early concept stage right now, so there's plenty of room for refinement.  For a yard this size, there's only going to be one master retarder, so there's only a few inches lost on each track due to the grades.