I have read numerous sources that recommend the drill track for a classification yard should be as long as the longest yard track. Frankly, I’ve never understood the reason for this either on the prototype or the model railroad. A prototype freight train could be a mile long. What is the purpose of having a drill track long enough to handle the whole train at one time. When breaking down a train that is on the arrival track, is the switcher going to pull that whole train onto the drill track and then start pushing each block of cars onto the appropriate classification track. Would a switch engine even have the power to do this? It seems to me it would make more sense just to pull a single block from the train at a time, maybe two or three blocks if they were small, and then push them onto the appropriate track. The same number of back and forth moves would be required. What is gained by pulling the whole train onto the drill track? Is there something about this process I am not understanding?
One benefit I could see to such an arrangement where the entire train is pulled back is that an A/D track is freed up, making room for new arriving trains and freeing up power. However, this would only postpone clogging as the yard would be unable to keep up.
The other is the opposite move, when moving cars out of the yard body and into the A/D track. You don’t want to have to split up a ready block of cars in a yard track in order to move them back to the A/D track.
Just my 2 cents. I have no expertise in the field. 
Its not a prototype “rule”, its a model “rule”. That’s becaues a model train is a fraction of the size of a prototype train. Real flat switching yard only switch cuts about 30-40 cars long. But most model trains are in the 15-25 car range, half the size of a real cut. So a lead as long as the longest track makes sense on a model railroad.
Yes a switcher has the power to do this. Actually on some hump yards a 1500 hp engine will power a slug too (making it in effect two 750 hp engines) and that can move the same train it took a set of 3 sd40’s to get over the road.
95% of the time you aren’t setting over blocks, you are classifying the cut, which means the cars go into various tracks in groups of ones and twos.
Because you don’t have to reach all the way into the origin track it s faster. you also clear a track for an inbound train quicker. If I suck and entire inbound track back onto the lead I have cleared an inbound track and if the yard is designed right, I can be switching the cut while another train is yarding in the track.
Dave H.
Without the drill track you would be fouling the main to section a departing train or the same for breaking up the inbound for classification.
I understand the need for the drill track but not for why it needs to be so long.
I think dehusman hit the nail on the head. It is more important in the model world than the real world (though probably useful there, just not as much). I think the critical thing is that trains in our world tend to run more frequently, but yard tasks don’t take propotionally less time. Some less, but not as much less. (There’s some writing on this, I think Bruce Chubb referenced it in his book on operation.) So it is more important for us to keep our main clear, or we will soon find ourselves only waiting on the yard.
A classic case of what is sound advice in the model world getting to be seen as a rule for the real world… but it isn’t a rule.
The reason for the MRR scenario is usually that our limited space/length means that we are forced to run short trains. We are never looking at running scale 1 mile long trains.
The real RR don’t as a general rule switch one mile trains in one hit. They also tend to run these trains between very big yards that they can fit them into (logically).
A % of those very long trains will be unit trains that aren’t going to get switched and that will be serviced at purpose designed facilities. Coal and IM are the big examples.
Once you get to the rest of the world… the very big mixed trains tend to run between hump yards. These are high maintenace yards on which long strings of cars are shoved over the hump(s) to run down the other side singly or in cuts. In this scenario the cars/cuts are sorted to roads remotely from a control tower with the assistance of car retarders and remote switching. The break up for classification is made remotely. The loco(s) are not drilling the cars all the way into each road that fresh trains are being built up on. All the hump loco does is shuffle forward as instructed.
For flat switching the loco crew needs to be able to “see” what is going on at the propelled front end and react quickly enough to not do damage - either by bangng into things or by not stopping if a car derails. They also need to be able to “see” that they have drawn back far enough to clear switches before the next shove forward - flat switching ir=s a lot of to-ing and fro-ing. Personal radio helps this a lot… so long as you have a good signal.
The big issue on how much you switch in is therefore not doing damage. The next issue is the available space for the drill track. Modern facilities built out-of-town can have as much new space as they
The two Daves pretty much covered the waterfront on track length and reasons therefore. To address switcher power:
- In days of yore, Norfolk and Western routinely assigned Y-class mallets to switching duty.
- Both PRR and NYC owned a few articulateds - all of which were used as hump engines, not road power.
- Diesels in switching service can be run with one or even two slugs. Horsepower isn’t an issue at 4-6 mph, but tractive effort is.
The one thing we often overlook is the sheer length of prototype yards. If accurately modeled in HO, some would stretch well over the length of a football field. I’m trying to give that impression in less than 20 linear feet (plus some for the partially-hidden main drill track[:-^].)
Chuck (modeling Central Japan in September, 1964)
In Janesville, we have a track called the switching lead. It is about 25-30 cars long, about the same as the longest track in the yard. It hooks into the main at the west end, and the yard (tracks 1-7 and the ladder lead) are to the east, downhill. There is also a crossover between the ladder and the lead, so that you could have the engines on the main and put cars into the yard.
The yard has not been expanded (or maintained decent) since the days of steam. It is a pain bringing in the 100+ car train from Chicago to dice it up to where the cars go to. Longer trains usually sit on the main for a departure track. That will fit ~95 cars. Then the switching lead is open, to get some moves done in the yard. Our train to Chicago ends at BRC Clearing, a large hump yard.
With the engine pointed east, the engineer on the right side of the engine can see all the switches, and the ground man making cuts, etc. Before radios, you wouldn’t want to drag out too many cars, as the hogger wouldn’t be able to see what was going on.
jecorbett
On my home layout I usually am the yard operator. I have 5 yard tracks plus the A/D track and associated smaller tracks (Caboose, etc.).
Each of the yard tracks will hold 2 cuts of cars that would make a typical length train. Off the end of the yard (which is a fairly close prototypically accurate representation of the real Conrail Phillipston yard) is my Drill track.
Last Thursday night, as the OPs session was winding down, most of the trains were coming into Phillipston yard from both the South and the East. So I was getting swamped rather quickly. I had 5 trains in less than 10 real minutes that I had to make room for!
With the long A/D track I was able to have the arriving trains drop their power and move to the other end of the yard while I was pulling the just arrived cars onto the A/D track. I then begin classifying the train all while the engine crew was moving to the other end of the yard and moving their caboose to the Caboose track. Then the next train would pull into the A/D track. By the time that engine was out of the way I had the first train’s cars classified and was able to move to the A/D track and pull then next train to clear for the third train due in.
To make a long story short, I was able to keep up with all of the arriving trains and have them all classified almost before the last engine had the caboose put into the caboose track.
The model yard is always the place where the bottlenecks happen not out on the road, unless the Dispatcher is asleep!
On my layout the yard operator can sometimes not do much of anything once the session has begun depending on the number of train that need to be run that session. We do a continuous (al
First a yard crew can move more then 30 cars at a time.As a yard brakeman I recall moving cuts of 75-100 cars.We had to switch long cuts in order to get our work done.You see a heads up yard crew could and can flat switch 1200 cars in 8 hours.The 14 months I work as a yard brakeman we was not hampered by a switch lead.
A switch lead should be used on a layout so yard switching won’t interfere with the main line operation and it makes good sense to have that lead ad long as the longest yard track or better as long as the A/D track.
A fallacy among modelers is the myth of fouling a main while switching cars…There are small out laying yard where we would routinely use the main as the switch lead with the DS approval.
The Benson yard here in Bucyrus is one example.
I agree with Brakie here. This is one of those cases where modelers don’t know what they think they know. With the higher density of model traffic, yes it makes sence to be able to switch without fouling the main. However, while nice, it’s not absolutely necessary to not foul the main while switching.
It also depends on the type of switching you are doing. When flat switching, I’d rather not hold on to more then 30 or 40 cars if I can help it. Flat switching can be alot of pulling and shoving. If I’m humping, I’ll tie on to the entire 150 cars and push them right over the hill.
I too have working numerous places where the main is used as a switching lead.
As for switching power…when flat switching I want something with fast acceleration. My favorite is two GP38s. For humping, I want slow power, like a SD40 + a slug.
Nick
I appreciate everyone’s input and it re-enforces my belief that a long drill track is not as important as a lot of publications make it out to be. In my own case I have a very large yard by home layout standards. My longest A/D track is about 25 feet long and the yard is double ended. Although it makes it possible for me to run very long trains, as a practical matter, 25 cars is a better limit. Anything over 15 requires either MUing or helpers to get up the ruling grade. The drill tracks at either end of the yard are 4-5 feet and to me that is plenty long. I’d rather break up or make up a train in several bites rather than do it all at once anyway. Being a lone wolf. I won’t be creating bottlenecks. I think for small to medium sized layouts with yards that aren’t that big, it might make more sense to have a drill track as long as the longest track but I can’t imagine anyone needing one more than 8 feet and even that seems like a luxury.
My yard lead is not the length of my longest yard track. You can take a look at the pic in my sig. The drill track in Deming goes past the passenger stn and then ties back into the main. Operationally I like it. My longest yard track is 17’ and the yard lead is about 7’.
The only time I wish the lead was longer is when there is a car that I need at the very back of a cut on one of the yard tracks. To get just one car I need to take that cut of cars out in three sections and move them to a different track. Or I put in a call to the dispatcher to get clearance on the main and pull the whole cut out in one move.
It’s important to note that you said the drill track needs to be as long as the longest YARD track… that doesn’t translate to the length of an over the road train.
My train length (in N scale) is typically 20-25 cars, or about 6-7’. My yard tracks at their longest are about 48" to 54". My drill track will be 48"+. My A/D tracks will be train length, so I can receive a train from the road. My switcher then grabs the back, pulls half of it, classifies it, then pulls the other half. If there’s room in the yard and lot’s of traffic coming and going through the A/D tracks, I can pull a train apart and shove it into a couple of classification tracks to make room.
Lee
Part of the reason for long drill tracks, was the fact that twenty years ago we did not have DCC. The drill track and yard had to be electrically seperate from the mainline so the yard switcher did not have to go out onto the main. This was not a problem on the prototype railroads. With the advent of DCC the switcher can go out on the main and not cause any electrical problems with running a train on the mainline.
Rick
We’re all three (sometimes protagonists) in agreement [:O]
Brakie… can you elaborate on the issue of the loco crew being able to see the switches please? Also, did you ride the cars much in the work? (Not that we can model this but I’m fascinated by DVDs I’ve seen of US switching…)
Nick… why a limit of 30-40?
Something that occured to me after my above post was the issue of slack running in and out when flat switching… is this part of your thinking? Brakie… what’s your take on this? What difference would cushion draw gear make please?
Nick… I can understand the big steady shove over a hump… but why do you want the different power for flat exactly? Why GP38s? Would GP 38-2s be as good? Would GP 35s or 40s come close? How about U25Bs or C424s? (Okay, I am stirring a bit
jecorbett,While it is nice to have a long switch lead it may not be practicable on smaller home layouts.This is where we must divide facts from fiction from the writer’s views in reading layout books and then planing our layout…We may be building a a bedroom layout for solo operation while the author of the book is rattling on about a basement size layout with several operators.
I urge everybody to watch these catch all words found in books and magazines.
" Layout Standards"(questions:Whose standards?)
30" or larger curves(Nice if practicable for OUR SPACE)
Stagging yard(why bother for solo operation? Use the space wisely instead for more industry)
I could go on and point out more but,I think you already have the real picture.
The cold hard fact is we need to design our layouts to our givens and druthers in line with our space limitations.USE ALL SPACE WISELY.
Dave-The-Train asks: Brakie… can you elaborate on the issue of the loco crew being able to see the switches please? Also, did you ride the cars much in the work? (Not that we can model this but I’m fascinated by DVDs I’ve seen of US switching…)
First no we would not ride the cars in yard switching.The cars was “kick” and not push to a coupling…That would take to long.We brakemen would line the switches for the next move according to our switch list.The conductor would act as a “pin man” and uncouple the cars for the kick.
The engine crew does not need to see the switches just the man on the ground giving hand signals-this was done on the PRR,on the C&O under Chessie it was done by radio like today.
Now some railroads used a “switch light” A blinking white light means to PULL FORWARD,red light means STOP while a green light mean to BACKUP.These lights was on poles in the yard and on switch leads.These was controlled by the brakemen or conductor…The fireman would relay the signals if the switchmen was on his side due to the location of the switch stand .
Of course there are yards that are known as a “reverse yard” or a “forward yard”.All that means is the switch stands is on one side so,the yard switcher would be turned to where the engineer was facing the switch stands so he could see the hand signals of the switchmen.This died out with the use of radios in most cases…
Rick,Sorry DCC has nothing to do with a yard lead or using the main for a switch lead.This idea dates back to the 50s.A yard lead is needed because most home layouts are design as a continious loop operation.A toggle switch could be use for a shared block between the yard operator and main line operator if the layout was large enough.