Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Operations question

1090 views
9 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    March, 2018
  • 20 posts
Operations question
Posted by Cymrych79 on Tuesday, June 05, 2018 6:47 PM

Hi all, 

Forgive me if this should have gone elsewhere, but I didn't see any ops posts on any of the 4 boards, so Layout seemed the most appropriate to me... Mods, feel free to move if it would be better served elsewhere!

I have a small-ish N scale staging yard-to-staging yard, round the walls type shelf layout, and I'm just getting into operations. Not full blown yet; still only have around 50-60% of the full-up rolling stock I'll eventually use, but enough to run 3-4 trains of 9-11 cars out of staging each session. I'm using car cards and waybills for car forwarding, and thus far, simple sequential train scheduling one after the other, with breaks in the mainline through freight to run locals out of my small (3 track, about 32 car capacity) on-layout classification yard. Eventually, timetable and train orders will be implemented. Most of my waybills are 4-cycle, which effectively means that at the start of a session there are roughly 3 times as many cars in staging as on-layout at industries: one car that is coming onto the layout next session plus two more currently bouncing from staging to staging as cars in a through freight until their time to come onto the layout proper arrives in a later session. All cars going to or coming from on-layout industries pass through that single classification yard, which, due to it's small size, means I receive both a north- and a south-bound through freight, collect the cars for a turn with the yard switcher, and run the turn right away. Then through freights 3 and 4 arrive, and turn 2 gets to work.

Anyhow, as I said, I'm not full-up yet, just tinkering. And so far, it seems to be going well. Except, with only have two through freights each direction, I'm finding I leave cars in the classification yard that still need to go to staging to complete their cycle. 

So my options are three that I can see: 1) Leave them there, and pick them up on the first through freights of the next session. This will have the effect of adding an extra session to about a third of the cards coming out of industries, since their waybills won't get turned until after the end of the session in which they actual arrive in staging. Or 2) Get a little ad hoc with my through freights, and add a short, third thru freight in each direction hauling only staging-to-staging cars, specifically to pick up the cars otherwise hung out to dry in the on-layout classification yard between sessions and get them into staging. This would both clear the classification yard, and keep all waybills cycling together. Or 3) Cluster all my cars going onto the layout into the first train out of staging, effectively making a local as it won't have any cars left to run through to the far end staging. This might work now, as I'm only shoving 13 or so cars into the classification tracks per session, but as my inventory goes up this will be hard to maintain (although, I only plan on at most 30 cars going to industries, so technically, I have the room in the yard. It just would be a pain to block for the turns.)

Now, this might clear up on it's own once my inventory gets closer to full and I have more through freights to play with. But as I only envision 4 each way at most (the mechanical limits of the staging yards), it might not.

I'm sure I'm not the only one to have stumbled into something similar. What have you guys with much more experience in operations done in such a situation?

Tags: Operations , Ops
  • Member since
    March, 2017
  • 55 posts
Posted by RobertSchuknecht on Tuesday, June 05, 2018 8:29 PM

Cymrych79
Leave them there, and pick them up on the first through freights of the next session. 

This is what I would do. There is no reason every car must go through an entire cycle each operating session. I also don't see a reason to run every train in an operating session. 

 

If I were to run every train during a session I would have to run ten trains, eleven if a coal train is due. It could take me all day to cycle through every train.

  • Member since
    March, 2018
  • 20 posts
Posted by Cymrych79 on Tuesday, June 05, 2018 10:36 PM

RobertSchuknecht

This is what I would do. There is no reason every car must go through an entire cycle each operating session.

Honestly, that's more or less what I'm discovering through running the sessions in sequence, trying different things. I first tried the short through freights at the end to collect cars from the classification yard, but then it seemed as if my leading through freights, which drop the session's first cars for on-layout delivery on their way through the yard, were unusually short heading to staging afterwards. But if I have "last night's" late arrivals to grab, then i can maintain my (loose) goal of keeping trains in that 8-11 car range throughout the session. AND, not have to run two extra through freight runs. As a bonus, it's probably a bit more prototypical, too, leaving the late stragglers overnight.

I probably won't run all trains in one go much either, once I'm stocked up. As it is, I can run my 4 through freights and 2 turns in a little over 2 hours. Add on 2 or 4 more through freights and a third turn, which is about what I anticipate once my inventory is built up, and I'm looking at at least 3 hours or so. And that's not counting two coal drags, which still await the track laying team!

  • Member since
    November, 2002
  • From: US
  • 2,232 posts
Posted by wp8thsub on Tuesday, June 05, 2018 11:03 PM

Cars move when they move.  It isn't necessary to consider how much of a "cycle" on the car card gets fulfilled in a session.  I have cars that may take several sessions to get to the location shown on a particular side of a car card.

An example from my layout...

DAY 1

Let's say boxcar WP 38056 is in west staging (Elko, Nevada).  It's billed to the Sierra Pacific plywood mill at Raft River, on the end of its namesake branch.  This trip, it's in a block of "Lakeview shorts" in train CMS (cars to be set out at the yard in Lakeview, UT, the only stop the CMS has on the subdivision, so they can be distributed to the local jobs that work on the sub).  Problem is, the Raft River Turn doesn't go to Lakeview at all - the closest it gets is the branch junction one station east of there at Cedar.  Cedar has a company business track where cars destined for the branch are set out by another local called the Roadrunner that's based out of Lakeview.

When WP 38056 reaches Lakeview, the Roadrunner has already tied up for the day, so it waits for the next day's train.  We're through with one session, and the car has not yet completed one side of the car card.

DAY 2

The Roadrunner blocks WP 38056 along with any other cars headed for Raft River, and heads east with the Raft River block first out behind the locomotives, and the remaining blocks behind it.  At Cedar, the Roadrunner sets out the cars for the branch on the company track, pictured above.  The same track is also used for some of the loads coming back off the branch and headed west.

The Roadrunner's crew leaves the paperwork for WP 38056 at Cedar.  By this time, today's Raft River Turn has already run, so the car still hasn't reached its destination for the second session in a row.

DAY 3

Today's Raft River Turn is called from the yard at Junction City, on the opposite (east) end of the sub from Lakeview.  It heads west to Cedar, where it picks up all the cars left for it by yesterday's (last session's) Roadrunner.  It then runs down the branch, fiunally spotting WP 38056 at the Sierra Pacific mill.  Three sessions in and the car has completed one side of the waybill.

DAY 4

The Raft River Turn runs again today, but the mill hasn't finished loading WP 38056.  It stays put.

DAY 5

The car card is flipped to the next side.  The load is billed to a customer off line to the east, and will be interchanged with the D&RGW at Ogden, UT.  Today's Raft River Turn pulls it and brings it, along with the other eastbounds off the branch, to the yard at Junction City, where the local ties up.  

The yard crew blocks WP 38056 with other cars to be handed over to the D&RGW.  There are no remaining eastbounds today taking blocks for the D&RGW, so the car remains in the yard.

DAY 6

Eastbound train GGM makes its one stop on the subdivison at Junction City.  It sets out a block of shorts, and picks up a D&RGW block that includes WP 38056.  The car ends up in Ogden (east staging) and now the move from the second side of the car card is complete.

 

The above series of movements is typical for cars billed to on-line customers on my layout.  While the events described took six sessions, they could potentially be completed in only two, or they may take more than six.

It's easy to get lost with individual car movements.  I like to think in terms of blocks.  Concentrate on getting the car into a block, and then getting the block moved to its destination.  Most cars on the prototype don't get expedited treatment, and the process takes as long as is necessary based on the trains doing the work.

Rob Spangler

  • Member since
    March, 2018
  • 20 posts
Posted by Cymrych79 on Tuesday, June 05, 2018 11:49 PM

wp8thsub

Cars move when they move.  It isn't necessary to consider how much of a "cycle" on the car card gets fulfilled in a session.  I have cars that may take several sessions to get to the location shown on a particular side of a car card.

That makes perfect sense. I think I may have been caught up with the idea that each waybill cycle starts and/or ends in staging, therefore all cars should start and/or end each session in staging. Due to my layout's small size, I don't have many places where cars can get left without a train, except for my chief classification yard, so it wasn't something I even thought of until now!

With cars sometimes taking multiple sessions to achieve one part of their waybill cycles, do you ever find yourself unbalanced in your staging yard(s)? Such as, with too few cars to make up a scheduled train?

  • Member since
    November, 2002
  • From: US
  • 2,232 posts
Posted by wp8thsub on Wednesday, June 06, 2018 12:09 AM

Cymrych79
With cars sometimes taking multiple sessions to achieve one part of their waybill cycles, do you ever find yourself unbalanced in your staging yard(s)? Such as, with too few cars to make up a scheduled train?

"Too few" cars is never an issue, as the train can go out with whatever cars are available, just as actual trains vary in length.  I use active staging, so trains are continuously being staged and re-staged during the session (as such, the staging operator can adjust trains as appropriate to keep things moving).  Without active staging, you should still be able to run a train with whatever's there.

Then again, sufficient capacity was designed into the staging and other yards to account for fluctuations in traffic.  Car movements tend to average out at my place so that trains usually end up with a similar number of cars.

Rob Spangler

  • Member since
    March, 2018
  • 20 posts
Posted by Cymrych79 on Wednesday, June 06, 2018 12:51 AM

Thanks Rob.

I guess the real difference between the prototype and our running is that I'm sure there is a minimum train size in real life where the operating costs outweigh the income. But, we definitely don't have that concern, so yes, why not send the train regardless of how short it may be?

I don't have much layout space, but fortunately I built in a degree of surplus capacity to my staging yards. Not a great deal, but enough to stockpile, say, half a train worth of cars in each yard if I need to add some bulk for appearance sakes (or replace a car on the fly due to damage, etc). But hopefully that won't be much of an issue, as everything I've thrown at my pike so far has resulted in fairly balanced numbers in the yards each session. There's some fluctuation, of course, and I still need to run a few sessions not worrying about where a car ends up in the cycle. And I'm still tinkering with different blocking scenarios to increase my on-layout efficiency. But over all, I think I'm in good shape.

  • Member since
    July, 2010
  • 126 posts
Posted by grinnell on Monday, June 11, 2018 1:02 AM

Random fluctuations will naturally result in varying train lengths. Short trains are not a problem, but some trains can get to be longer than the length of the staging tracks. Hence the need for a "tonnage limit" and if the train would be longer than the staging tracks, some cars have to be held in the yard for the next train. If very many cars have to be held and the yard gets more than about half full, the yard tends to choke and you'll find you have to remove some cars from the layout.

Grinnell

  • Member since
    September, 2003
  • From: Omaha, NE
  • 9,282 posts
Posted by dehusman on Monday, June 11, 2018 7:22 PM

In the short term things will be a little unbalanced.  Surprise, real railroads aren't balanced either.  Shippers ship more on Thu-Fri-Sat than they do on Sun-Mon-Tue so railroads have to run different numbers of trains on different days.  Plus if Chicago and LA each run two extra trains on Fri, that means that the heavy day for someplace in the middle is Sun or Mon, so the heavy spot moves around.

What you have to do is operate several sessions to get the flow evened out.  I don't use 4 cycle waybills, I use 2 cycle waybills.  That allows more control on trains entering the layout.  If I want local 491 to have 8 cars on it then I bill only 8 cars per session for trains coming out of staging for industries serve by L491.  I can control how long cars dwell in the yard by which train gets which cars.   If the cars are going to roll till next session then a train arriving at the yard later in the session might have more of those cars than a train arriving earlier in the session.

Each session is 1 8 hour shift.  If I run 3 through freights out of staging per session, the first train will have more cars for locals running the 2nd half of the shift.  The middle freight will have more cars for the trains running the first half of the next shift and the last train will have more cars for trains in the next shift.  Not all cars on a freight will be for one local, some cars will roll.  But if I feed just 8 cars a shift onto the layout, over time there will be generally only 8 cars  on each local.  If I have the local pull a similar number of cars from industry, they will feed the same number of cars back to the yard to go back to staging.  

All this is very easy to control with 2 cycle waybills.

Dave H. Painted side goes up.

  • Member since
    March, 2018
  • 20 posts
Posted by Cymrych79 on Monday, June 11, 2018 7:59 PM

dehusman

All this is very easy to control with 2 cycle waybills.

I'm pretty space limited and can't really store cars in my staging yards for later insertion into a train. So I've operated such that basically everything moves every session, but about half of the cars are just passing through from west to east staging or vice versa. 4-cycle waybills work great for that, as two cycles of the four are dedicated to just being road traffic cars to fill up through freights.

I use 2-cycle for captive service cars; from an on-layout industry to unload, then to a dedicated off-layout industry to reload. Which works fine for a unit train or a dedicated block. But running single cars that way gets really repetitive, seeing the same 2 cars ping-ponging back and forth, at least on my short layout. With a larger block, though, it looks more protypical-like.

4 cycles, with some 3 cycles mixed in, really seem to keep things mixed up pretty well. And since 60% or so of my cars make it back to staging each session and have to be staged with the old 0-5-0 for the next session anyhow, I can break up the oddball cars that somehow get stuck together for more than a few sessions in a row by putting them onto different freights for the next session.

I have observed what I've been calling a "tidal swell" in my car movements. Basically, since there aren't exactly an equal number of industry cars heading east and west, nor exactly equal numbers in through freights going each way from west to east staging or vice versa (and of course, why would there be??), where the peak volume ends up at the end of the session changes cyclically as the waybills go through their progression. I'm a nerd for the math so I've been plotting my results. What i've seen is not only a rotating peak volume location (first the classification yard, then west staging, then east staging, then on-layout), but also cycles in the magnitude of that peak (west staging last time had the peak with 8 extra cars, then four cycles later it had 5 extra cars, aka, my "low tide"). Which makes sense, as I'm using 4-cycle, 3-cycle and 2-cycle waybills and the pattern of cars only repeats every 12 sessions.

Anyhow, as I said before, I'm in good shape. Things are running quite smoothly. I think I might have been overthinking things before, mostly because my roster is only about 50% complete so any cars not reaching staging at the end of the session really made an immediate impact, visually at least. Operationally, not so much! And I see now that as my inventory builds up and I bring the third round of through freights online, it'll matter less and less and be much less noticeable to boot.

Thanks, 

Jason

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!