Operations: Direct access from classification to main?

[MVW]

A question for those interested in operations: Which is better?

1) Classification tracks isolated from A/D yard. Classification of cars can continue while other trains arrive and depart. Downside is that you can't simply couple a road engine to a train assembled on classification tracks and depart the yard.

2) Direct access from classification tracks to mainline. Downside is that classification stops while trains arrive or depart.

That's the question I'm facing as I'm about to construct my main yard. I had originally designed it for #2 above. The I read the extended discussion in "The Best of the Railwire Archives" about the design for Lee's new yard on his Western Maryland. I'm now leaning toward #1, which seems to make more sense (and is probably closer to prototypical operations). Unfortunately, I have little experience in this regard, and would like the input of some experienced yardmasters before the track goes down.

This will be a relatively busy yard. The plan is for two A/D tracks plus a thoroughfare track to provide access to roundhouse/engine servicing (this could serve as a third A/D track in a pinch). Five double-ended class tracks, a double-ended caboose track, and another thoroughfare track for switchers.

Maximum train length is about 30 cars. The yard has drill tracks at both ends, and I briefly thought about providing direct access from the main to class tracks at one end. This would work well for trains arriving/departing from one direction. But I can't see backing a 30-car train into or out of the yard without more than occasional mishaps (not to mention tying the mainline up for extended periods) for traffic to or from the other direction.

Your thoughts?

Jim

[seusscaboose]

Option 2 allows trains arriving to be broken down and reclassified on departing tracks while at the same time adding cars from the classification yard.

The problem is that cars are now NOT blocked... Since cars from arriving trains are next to cars from the class yard... That is only an issue if blocking is important to your operators ...

[wm3798]

On mine, I've got basically four different types of trains that get processed through the yard.
1.  Fast freights, which come from staging, then do a block swap for pick ups and set outs.
2.  Coal and Grain extras, which may just roll through, or may have pickups and set outs
3.  Locals, which obviously handle switching duties at various points along the line
4.  Industry-specific turns that handle traffic to the paper mill primarily.  This is basically a turn that goes from the yard, drops off cars at the mill to be switched by the mill crew, then picks up whatever's there to come back to the yard.


Starting at the far left, the track with the train on it is the long siding, followed by the two mains.
Next are three tracks that can be utilized for A/D.  The first is generally kept open for locomotive run-around movements, then two pure A/D tracks. 
Next is the Piggyback/Auto Rack tracks, then 9 classification tracks.
The class tracks and A/D tracks are all double ended so they can be worked from both ends.

Through experimentation, I've found that the best way to handle the fast freights is to roll them in on the main, and block the cars to be picked up on the A/D tracks.  These trains usually involve a power swap, too, so the engines are cut off from the front, and the set outs (which are pre-blocked coming out of staging) and the set outs are pulled from the back.  The train is then reassembled on the main, fresh  horses are added to the front, and a new caboose will be tacked onto the end of the fresh cut.  This process keeps the longest trains from clogging up the A/D tracks.

Coal and Grain extras that have pick ups are usually assembled on the long siding outside the mains, so again, the through train can simply do a pick up and set out maneuver out there.

Longer locals, such as those bound for the Thomas Sub and Elkins, are typically assembled on the A/D tracks, then held there until released by the dispatcher.  This is also true of the Paper Mill turn.

Shorter locals can be built right on the class tracks, or if space is available, on the A/D track.

There are full interlockings on the main at either end of the yard, so there's total flexibility to allow through trains to pass if another is blocking a main.  While we haven't had a full blown ops session since I built this, I've done a lot of dry runs and it seems to work pretty well.

Bottom line is, if you have a through train that just needs a block pulled and another tacked on, do that on the main so you're not bottling up the yard crew.  Also, depending on how extensive your schedule is, I've found that it's better to have more class tracks that are shorter than fewer that are longer...

Lee

[conrail98]

Why can't you do both? I've seen plenty of model railroad yards that do allow for access from main to A/D without disturbing classification but there is a switch further down the yard lead that also acts as a connection for the class tracks to the A/D track(s). Here's a design I had been looking at doing but pretty much with a standard yard design I've been using:

https://lh3.googleusercontent.com/-jbTRcAPU_Bs/TwnlT8tWJ9I/AAAAAAAAEFE/-Q_RfZyBHks/s1600/cr-c-p-3.0a.jpg

The whole thing is based on two yard designs I've seen on the LDSIG site by Mark Lestico, his own and another he contributed to. The main is down the middle, with engine facilities on the opposite side from the yard. There are pluses and minuses to that, but that's not what you're looking at right now. The track next to the main is used as an A/D and you can get to that without affecting the ladder and the switchlead, which is the track going to the top and right. Notice on the top-right a switch back from the lead to the main. This would give any train departing from a class track direct access to the main going in that direction, but the lead is on the side of the yard that most trains will go, especially locals built on the class tracks.

The layout I operate at every month has the ability to do both also, however, it's a double-ended point yard, meaning trains terminate and originate there, but the lead is on the opposite side from where the trains come from/go to. This allows trains to be built on the class tracks and depart directly from them to the main,

Phil

[Ed Kapuscinski]

I think it's going to depend entirely on the scale of operations. If you have a pretty busy railroad, like Lee does (lots of trains and not a ton of distance a busy railroad makes), keeping classification going at all times and keeping movements onto and off of the mains fluid are real benefits.

However, if you've only got two trains a day coming and going, it's not so big of a deal.

The decision point is if you're going to use your A/D tracks as true A/D, or just arrival, and if you're going to be classifying cars by train or by destination.

If you do so by destination, it means any departing train will be made up of multiple blocks. If by train, you can pull the thing straight from the class track onto the main. However, if you do it by destination, it means you need another job to pull cuts of destination blocked cars and assemble them into full trains (or cuts for adding to a through train) prior to departure.

[MVW]

I appreciate the input, guys. I'm in the middle of a little home remodeling action at the moment, but will comment more this evening.

Thanks!

Any other thoughts?

Jim

[Specter3]

I would say if you have the space then why not be more operational in design and go with the first choice.

[NS-CRE]

Like Phil said above, you can do both.  On my layout, classification can take place and is not interrupted by the arrival and departure of trains from the A/D tracks.  However, some trains can leave straight from the class tracks, which does mean interruption.  Since that's at the yardmaster's discretion, it's only his fault if he has to stop switching because a train is pulling from the class yard.

Most of the time, trains arrive and depart from the A/D tracks, but there are some special cases when it's just about as easy for a crew to tie power on and make the pull from the class yard rather than having the yard crew build the train by pulling cuts and moving them from the class tracks to the A/D tracks.

[MVW]

Thanks, everyone, for the input, photos and diagrams.

As a few of you mentioned, I may attempt to do both. This will be possible on the west end of the yard; on the east end, the lead to the roundhouse/engine servicing will be in the way.

Lee, thanks for the detailed description of your yard and how it's used. My operational plan is the pretty much the same, except I expect local industry turns to handle all switching instead of handing cuts over to other crews.

The one drawback I have is that I'm pretty much stuck with a single-track main.

As I'm building a large layout in small stages, the operational plan is in a state of flux. I'd eventually like to have a train (both frieght and passenger) into or out of this town every 5-10 minutes. Whether that will be possible with a single-track main remains to be seen.

I'll have the east end of the yard up and running in a month or so, and I'll be doing some limited operations using it as a single-ended yard until next fall. That may help inform my decision as to what happens on the west end. At the moment, I'm leaning toward adding a crossover between the west drill track and the main to provide direct access to classification.

Thanks again, everyone! You've helped me think this one through a bit more clearly.

Jim

[cv_acr]

The problem is that cars are now NOT blocked... Since cars from arriving trains are next to cars from the class yard... That is only an issue if blocking is important to your operators ...

Eh?

You don't _have_ to have dedicated A/D tracks to properly block trains. You sort cars into different tracks to make up your blocks and build the blocks onto each other in any open class track to prepare an outbound train. The fact that the tracks are physically beside each other or separated doesn't really matter.

The main yard at my model railway club actually has no specific A/D tracks at all. [The prototype that it's based on] is not a division point, although it is located at or near the junction of a couple of different routes and supports a lot of local industry. [Some] mainline trains perform simple block swap lifts and setouts, and the only trains that originate/terminate are local trains. (With the exception of one daily train from Toronto which delivers local cars and typically plugs two whole tracks on arrival.)

[seusscaboose]

The one drawback I have is that I'm pretty much stuck with a single-track main.
Jim

single track mains make OP's more fun/challenging...   i don't view it as "stuck"... i veiw it as "a challenge"...

[Ed Kapuscinski]

A train every 5 mins? Are you modeling Enola? Sheesh!

Anyway, in that case, I'd highly recommend allowing your yard jobs to classify away, and taking one step out of the road crew's job, and having a dual ended yard, where one crew classifies, and the other builds trains out of the blocks that the cars have been classified into.

[MVW]

A train every 5 mins? Are you modeling Enola? Sheesh!

Anyway, in that case, I'd highly recommend allowing your yard jobs to classify away, and taking one step out of the road crew's job, and having a dual ended yard, where one crew classifies, and the other builds trains out of the blocks that the cars have been classified into.

Hold on, Ed. As I stated earlier, a train into or out of town every 5-10 minutes, both freight and passenger. I should have stated: freight trains into or out of this yard about every 15 minutes on average, probably slightly longer. But I was still refering back to Lee's comment about using his double-track main for some switching. With a single-track main and a heavy traffic pattern, I don't envision being able to tie up the main for long. But your description of working the yard is pretty much what I envision.

Seuss, you're right that single-track should be considered more of a challenge than a detriment. But double-tracking at least this city may have come in handy. Couldn't pull it off without exceeding reasonable reach distances, though, so it is what it is.

Jim

[conrail98]

Jim, if you are looking at a single track main, I'd really suggest you look at Mark's layout and his description of how he went about designing it.

http://www.macrodyn.com/ldsig/wiki/index.php?title=Cascade_Subdivision_-_N_-_Mark_Lestico

You'll want sidings on either side of the yard probably and maybe another within the yard limits itself, especially for passenger trains to get around. Just some thoughts,

Phil

[MVW]

Thanks for the link, Phil. I remember stumbling across his site in the past ... but it was a long time ago, and it had slipped off my radar. Great site and great layout. I'm looking forward to getting reacquainted with it.

Jim