Hi Vince.
One way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot.
In your example of a siding with a max capcity of 21 covered hoppers, if your max spot is 1 then you have to move all 21 cars to get them loaded or unloaded. In realistic practice, you wouldn't want to push all 21 cars into the siding because of the need to move all of the cars in order to spot them at the loading/unloading spot. You would most likely move half into the siding so they could be pushed through the loading spot. An additional storage track could keep the other half of the cars until you are ready to load/unload that next cut.
If you can only load/unload from a single location, then the max spot will be 1. If however there are 2 spots/doors to load/unload from then the max spot would be 2 because you load/unload 2 cars simultaneously.
Does that make sense?
Scott Sonntag
Vince Black But what with exactly is max spot capacity? What this says to me?
Vince BlackLet’s say I have an industry spur track which can hold three 50ft boxcars. There is a warehouse which can load/unload one boxcar at a time. So, is this capacity one car? Let’s assume when track is fully occupied, the warehouse is along the second car of car string. But I also can load/unload first car at the beginning of this process nad then the second one. So, may I say the capacity is two cars?
Vince BlackBut at the time first car is loaded/unloaded, the third car could occupy main track.
Vince BlackAnd how is it with grain loaders? It obvious the loader can load only one car at a time. Let’s say we have a grain loader siding which can hold twenty-one 3-bay covered hoppers. Grain loader is in the middle of this track, say ten cars could be spotted left from the loader, one under the loader, and ten right from the loader. OK, max track capacity would be 21 cars. But how will be max spot capacity? One car? Or eleven cars? Because if I move string of hoppers left or right, cars at the front or rear end also can occupy main track.
11. The elevator loads one at a time but uses a car puller (usually a winch device) to pull the cars past the loading/unloading hopper or pit. The RR will deliver the cars with the first car placed at the loading hopper and the rest trailing behind it (to one side). The industry will pull them through with their car mover until they've all been loaded/unloaded (and now parked on the other side of the hopper or pit).
Once again cars may NOT foul the main track in any way.
Chris van der Heide
My Algoma Central Railway Modeling Blog
I assume you're laying the basis for designing a trackplan, not merely asking a question about how the prototype operates.
I have determined that I need about 150 inches of storage space in staging to handle the amount of cars I will have spotted at the various industries around the layout.
The number of types of cars I want dicatates the number of industries (I want hoppers, cement hoppers, box cars, tank cars, woodchip cars). Then the space available for those industries dictates the length of the spurs, which in turn dictates the number of cars. If I spotted all of the cars at all of theor spurs, it would be a bout 150 linear inches of track needed. So that's what I need at the other end staging yard to hold the cars I'm going to swap out at the industries. Plus a few more feet of unused track with which to maybe move cars to and hold them out of the way until respotted. The additional feet could be simply in the form of the passing siding, extra inches on a long spur, or even the mainline since I run a one train at a time shortline.
Hope this helps.
- Douglas
Lakeshore SubOne way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot.
Not really. If there's only one actual physical [un]loading spot, and you fill the siding up to max. linear capacity, the rest of those cars can't physically be [un]loaded no matter how long they sit there. The spot capacity is 1.
If the industry received three cars, and they can [un]load from any physical location, but they only have "time" capacity to [un]load one car per day, the cars will either sit there for three days until released by the industry, or the RR will only pick up the car(s) that have been [un]loaded and released, leaving the other(s) behind. The spot capacity is 3.
"Spot capacity" is purely physical capacity in relating to actual loading spots, not how long cars will sit there.
cv_acr Lakeshore Sub One way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot. Not really. If there's only one actual physical [un]loading spot, and you fill the siding up to max. linear capacity, the rest of those cars can't physically be [un]loaded no matter how long they sit there. The spot capacity is 1. If the industry received three cars, and they can [un]load from any physical location, but they only have "time" capacity to [un]load one car per day, the cars will either sit there for three days until released by the industry, or the RR will only pick up the car(s) that have been [un]loaded and released, leaving the other(s) behind. The spot capacity is 3. "Spot capacity" is purely physical capacity in relating to actual loading spots, not how long cars will sit there.
Lakeshore Sub One way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot.
Yeah, that makes sense. On my last layout, I modified a structure kit so that the dock doors would accomodate 3 50 ft boxcars being unloaded at the same time.
In RR terms, I guess that is three spots, even if the siding might hold 9 cars.
Hi Chris, yes of course, you are correct. In the real world spot capacity is the number of loading/unload spots that are available.
I was thinking of it more in the model operations sense if there is only one spot and you have 3 cars to load it will take 3 time longer than if you had 3 spots to load. I didn't explain it very well.
Lakeshore Sub Hi Chris, yes of course, you are correct. In the real world spot capacity is the number of loading/unload spots that are available. I was thinking of it more in the model operations sense if there is only one spot and you have 3 cars to load it will take 3 time longer than if you had 3 spots to load. I didn't explain it very well.
Maybe, maybe not.
If you have one spot and a linear "capacity" of three cars, and you spot three cars, the other two cars can never be loaded. Only the car at the door/spot can be [un]loaded. Whether the other two cars are left on a yard track or the extra space on the spur, you're only spotting/loading one car/day.
Something like a grain elevator, mine tipple, etc. technically has one "spot" that cars are pulled by. Each car really takes a matter of minutes (less than an hour) to fill or dump. The RR only services it once/day so it can load 1 or 10 cars by the time the RR comes by again. It makes no difference whether the total time is 30 minutes or 5 hours since the RR won't be back again until tomorrow anyway.
If that industry in the first example was spotted with two cars instead of three (or the linear capacity was more like 5 to 6 cars with equal space on both sides), and they have a means to move the two cars around with the extra empty space on the spur to "re-spot" the cars on their own, they could load 2 cars/day. Which to the RR wouldn't be much different from a 2-spot industry.
Only the biggest, most high-volume industries with multiple shifts of operation are switched more than once a day. Some industries might only be served a few times a week.
Lakeshore Sub Hi Vince. One way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot. In your example of a siding with a max capcity of 21 covered hoppers, if your max spot is 1 then you have to move all 21 cars to get them loaded or unloaded. In realistic practice, you wouldn't want to push all 21 cars into the siding because of the need to move all of the cars in order to spot them at the loading/unloading spot. You would most likely move half into the siding so they could be pushed through the loading spot. An additional storage track could keep the other half of the cars until you are ready to load/unload that next cut. If you can only load/unload from a single location, then the max spot will be 1. If however there are 2 spots/doors to load/unload from then the max spot would be 2 because you load/unload 2 cars simultaneously. Does that make sense? Scott Sonntag
Yes, it makes sense perfectly. Especially information about grain loader track is very useful. Thank you!
cv_acr How many cars can actually be placed for loading/unloading. One door = 1 spot. If the track is at least three cars long, and the industry has a method of actually moving the cars on their own and can load/unload them this way, then sure max spot capacity could be 2. But you need at least a car length of track on both sides of the dock so the car(s) can actually be shifted into position. Absolutely not. The industry cannot shove a car out to occupy the main. The elevator loads one at a time but uses a car puller (usually a winch device) to pull the cars past the loading/unloading hopper or pit. The RR will deliver the cars with the first car placed at the loading hopper and the rest trailing behind it (to one side). The industry will pull them through with their car mover until they've all been loaded/unloaded (and now parked on the other side of the hopper or pit). Once again cars may NOT foul the main track in any way.
How many cars can actually be placed for loading/unloading.
cv_acr Lakeshore Sub One way to look at max spot is as the time factor for a siding. If it has a max capacity of 3 cars and a max spot capacity of 1, it means that it will take 3 time units to load/unload if the siding is filled to capacity. Along with the time to load/unload you also need to spot the other cars to that 1 spot.
Lakeshore Sub
That was another think I thought about, but didn't want to make my question post more confusing, so thank you for also explaining this.
cv_acr If you have one spot and a linear "capacity" of three cars, and you spot three cars, the other two cars can never be loaded. Only the car at the door/spot can be [un]loaded. Whether the other two cars are left on a yard track or the extra space on the spur, you're only spotting/loading one car/day.
This is interesting--why at least one other car won't be also loaded? Let's say the industry track at the warehouse will look like this:
<-main track end of track
/xxxxxxx/ spot /xxxxxxx/
/boxcar3/boxcar2/boxcar1/
("x" could be for example fence, something except spot)
I could get that the boxcar3 never be loaded, but I think boxcar1 could be loaded first:
boxcar2/boxcar1/ ->
...and then boxcar2?
Of course I suppose the warehouse contains sufficient amout of lading for two boxcars, although has only one door = spot.
Sorry for this very simple "drawing", I don't have any real example picture now.
Vince Black cv_acr If you have one spot and a linear "capacity" of three cars, and you spot three cars, the other two cars can never be loaded. Only the car at the door/spot can be [un]loaded. Whether the other two cars are left on a yard track or the extra space on the spur, you're only spotting/loading one car/day. This is interesting--why at least one other car won't be also loaded? Let's say the industry track at the warehouse will look like this:
If the entire track is crammed full of cars, and you can't foul the switch to the main track (remember, the industry is not allowed to do that), you absolutely have no room to move the cars at all, even if you had the ability to move them. Since you physically can't move the other cars to the loading dock, you can't [un]load them. You need the empty space to shift the cars around.
e.g.
Spotted with three cars, entirely filling the track.
/1/2/3/ <- all space is filled, cannot move any cars around at all. You can't shove to the right because the track physically ends, and you can't shove to the left because that would block the main track (not allowed). Only car "2" (at the dock) can be [un]loaded.
Spotted with two cars:
/x/1/2/ <- car "1" is at the dock and can be [un]loaded. Car 2 is currently off spot. When "1" is finished, you use a winch or other sort of car mover to pull or push the cars over into this position:
/1/2/x/ and now "2" is at the dock for unloading. You can't do this if all three spaces are filled because you're not allowed to push the cars out over the switch. And even if you could, or the spur simply had more length to the left, you're still limited by there only being room for one car to the right of the dock, so only two cars can be [un]loaded. Even if the spur was infinitely long on the left side, a third car could never be placed at the dock because the first two are right up against the end of the track on the right side.
So you can load 1 or 2 cars, but not three in this scenario.
The grain elevator is exactly the same: one car at the "spot" and the number of cars that fit to one side (the shortest side) of the [un]loading equipment.
Basically, any time you have a single spot located in the middle of the track, your loading capacity is 50% of the length of the track, because you have to push/pull the cars past the spot and you need equal space on both sides to do that.
cv_acr Vince Black cv_acr If you have one spot and a linear "capacity" of three cars, and you spot three cars, the other two cars can never be loaded. Only the car at the door/spot can be [un]loaded. Whether the other two cars are left on a yard track or the extra space on the spur, you're only spotting/loading one car/day. This is interesting--why at least one other car won't be also loaded? Let's say the industry track at the warehouse will look like this: If the entire track is crammed full of cars, and you can't foul the switch to the main track (remember, the industry is not allowed to do that), you absolutely have no room to move the cars at all, even if you had the ability to move them. Since you physically can't move the other cars to the loading dock, you can't [un]load them. You need the empty space to shift the cars around. e.g. Spotted with three cars, entirely filling the track. /1/2/3/ <- all space is filled, cannot move any cars around at all. You can't shove to the right because the track physically ends, and you can't shove to the left because that would block the main track (not allowed). Only car "2" (at the dock) can be [un]loaded. Spotted with two cars: /x/1/2/ <- car "1" is at the dock and can be [un]loaded. Car 2 is currently off spot. When "1" is finished, you use a winch or other sort of car mover to pull or push the cars over into this position: /1/2/x/ and now "2" is at the dock for unloading. You can't do this if all three spaces are filled because you're not allowed to push the cars out over the switch. And even if you could, or the spur simply had more length to the left, you're still limited by there only being room for one car to the right of the dock, so only two cars can be [un]loaded. Even if the spur was infinitely long on the left side, a third car could never be placed at the dock because the first two are right up against the end of the track on the right side. So you can load 1 or 2 cars, but not three in this scenario. The grain elevator is exactly the same: one car at the "spot" and the number of cars that fit to one side (the shortest side) of the [un]loading equipment. Basically, any time you have a single spot located in the middle of the track, your loading capacity is 50% of the length of the track, because you have to push/pull the cars past the spot and you need equal space on both sides to do that.
Chris, your discussion triggered a question if you don't mind.
The example above is of a small or modest sized industry, not of a grain/coal mine where the compnay might have a dedicated switcher/trackmobile that can get all of its cars loaded to be taken by the RR on one of the next trains.
Would the spotting in your example always be accomplished by the industry, a winch, or loader, or some device?
Or would the RR itself have to come by, move the next car to the one spot, come back the next day and spot the other, etc?
If its the latter, would the RR take the one loaded car with it and back to the yard, one at a time, or would it leave the loaded boxcar at the spur, and then the next, after shuffling them around in order and wait to take all three at the same time?
Thinking in terms of my RRs operations, if I have spotting duties amongst cars already on the spur, and then having to take one back with the train on the way back to the yard instead of waiting to take all three the next day.
Doughless Chris, your discussion triggered a question if you don't mind. The example above is of a small or modest sized industry, not of a grain/coal mine where the compnay might have a dedicated switcher/trackmobile that can get all of its cars loaded to be taken by the RR on one of the next trains. Would the spotting in your example always be accomplished by the industry, a winch, or loader, or some device? Or would the RR itself have to come by, move the next car to the one spot, come back the next day and spot the other, etc?
I've seen examples of industries pushing cars around with a front-end loader or tractor.
https://www.youtube.com/watch?v=PXUNrtJRsyY
Or you just mount a winch somewhere. (Lots of elevators don't have switchers, they just have large fixed winches to pull cars.)
It actually doesn't take as much as you might expect to move a single car. A person or two can move one by hand on good level track - skip to 8:30 on this video: https://www.youtube.com/watch?v=VGqZn5s_q_Y or this guy: https://www.youtube.com/watch?v=5Bqdek4C3yM
Keep in mind that if the RR comes in and moves it for you, you're going to be charged a switching fee for that, so anything you can do to avoid it, or just do it yourself...
Doughless If its the latter, would the RR take the one loaded car with it and back to the yard, one at a time, or would it leave the loaded boxcar at the spur, and then the next, after shuffling them around in order and wait to take all three at the same time?
If the RR is going to come in at all, they're going to pull the released car(s) that are ready for pickup. If they're in there switching anyway, there's not logical reason to leave behind a car the industry has released.
If they come in to specifically move a car to a different spot without actually picking it up, they're going to charge the industry for that.
I am not a RR professional, but my understanding is the basic drop off and pick up of the car is essentially included in the shipping charge. But any other moves above that you'll be charge extra for by the RR (unless you can make nice and bribe the crew on the spot to do you a favour "off the books"?).
I recall a quote attributed to a yardmaster from my freight days years ago:
"There's always room for one more car..."
About the warehouse, you wrote one door = one spot, but what if warehouse like this has 6 doors (I know, it's a model):
https://pin.it/4IV27Qh
So the spot capacity is 6? Or it is 2, becouse obviously only two cars can be loaded simultaneously there?
It's how many cars can actually be spotted for loading.
I think we're overthinking it now.