A question about max track capacity / max spot capacity

[Vince Black]

Hi, I would like to understand well what is max track capacity and max spot capacity. I know that many times track capacity is in feet, but sometimes also say how much cars can be spotted there. For this I can take an example of 50ft boxcars and when I say max track capacity is 3 cars, I know it is about 150 feet.

But what with exactly is max spot capacity? What this says to me? Let’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? But at the time first car is loaded/unloaded, the third car could occupy main track. So, in this case max track capacity should be only two cars? I think max track capacity say only how many cars I can set out there, but doesn’t say anything about how much cars can be loaded or unloaded there.

And 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.

[BaltACD]

Short answer - It depends.

I depends on WHO is counting and what the purpose of the count is.

A 1000 foot track - by defination will hold 1000 feet of railcars.

A industry building that has loading doors spaced to fit 3 40 foot box cars - CAN NOT have 3 50 foot box cars properly spotted as there is a different door spacing between 40 foot and 50 foot cars.  The industury track may have the footage to hold 3 50 foot box cars - but the 3 cannot be properly spotted at the loading doors.

[mudchicken]

Working Capacity vs Total Capacity vs Spotting Capacity  .... All different.

Track capacity is fundamentally the distance between the derails or the clearance points. Each railroad's standards vary on how the clearance point is set. (I'm used to track centers at 13 feet being where the clearance point is set. Others use 13-15 feet plus one car plus other variables. On signalled track, you start looking for insulated joints and staying out of the detector section. Multiple variations.

Engineers and trackmen measure the length of track as being from the point of switch to point of switch (or end of track)....Operating guys start at the clearance point and go to the other end clearance point or track bumper. Depending on the size of the turnout (switch), that difference in length can be several hundred feet. Kinda amusing when things don't quite "fit" with the funky operating math. "Total" (max) capacity sucks up a lot of no mans land (point of switch to clearance point), but also causes concerns for the switch crew filling an area to capacity or emptying it out.

(Have had lots of issues in recent history with architects and civil engineers trying to design new facilities, docks, doors, gates and buildings ... Lack of railroad common sense in the design phase may kill or maim a trainman ... They really don't like you when you take their shiny new facility out of service before it even opens.)

Was that track storage capacity with the slack run in or out?

How much tail room do you have? 

With grain loaders, are you figuring-in room for a switcher and someplace to get it out of the way? carmover (& set-off)? joe-Bob AgriDummy and his tractor?

[BaltACD]

mudchicken

Working Capacity vs Total Capacity vs Spotting Capacity  .... All different.

Track capacity is fundamentally the distance between the derails or the clearance points. Each railroad's standards vary on how the clearance point is set. (I'm used to track centers at 13 feet being where the clearance point is set. Others use 13-15 feet plus one car plus other variables. On signalled track, you start looking for insulated joints and staying out of the detector section. Multiple variations.

Engineers and trackmen measure the length of track as being from the point of switch to point of switch (or end of track)....Operating guys start at the clearance point and go to the other end clearance point or track bumper. Depending on the size of the turnout (switch), that can be several hundred feet. Kinda amusing when things don't quite "fit" with the funky operating math. "Total" (max) capacity sucks up a lot of no mans land (point of switch to clearance point), but also causes concerns for the switch crew filling an area to capacity or emptying it out.

(Have had lots of issues in recent history with architects and civil engineers trying to design new facilities, docks, doors, gates and buildings ... Lack of railroad common sense in the design phase may kill or maim a trainman ... They really don't like you when you take their shiny new facility out of service before it even opens.)

And bad things happen when Engineering switch point to switch point numbers get put into the TT instead of the Clearance Point to Clearance Point numbers when it comes time to meet trains.

[mudchicken]

Amen. (But it was the operating guy* who couldn't read the map that put it into the timetable.)

 

*trainmaster, road foreman, rules examiner etc.

** especially during blind shoves.

*** The federal tax man doesn't care about car capacity, he's taxing you on total track feet of rail you have out there. (ICC GO-1 of 1914 still applies... and those rules were written more by beancounters and taxlizzards than engineers/surveyors maintaining the maps & record.) 

[Vince Black]

mudchicken

Working Capacity vs Total Capacity vs Spotting Capacity  .... All different.

Track capacity is fundamentally the distance between the derails or the clearance points. Each railroad's standards vary on how the clearance point is set. (I'm used to track centers at 13 feet being where the clearance point is set. Others use 13-15 feet plus one car plus other variables. On signalled track, you start looking for insulated joints and staying out of the detector section. Multiple variations.

Engineers and trackmen measure the length of track as being from the point of switch to point of switch (or end of track)....Operating guys start at the clearance point and go to the other end clearance point or track bumper. Depending on the size of the turnout (switch), that difference in length can be several hundred feet. Kinda amusing when things don't quite "fit" with the funky operating math. "Total" (max) capacity sucks up a lot of no mans land (point of switch to clearance point), but also causes concerns for the switch crew filling an area to capacity or emptying it out.

(Have had lots of issues in recent history with architects and civil engineers trying to design new facilities, docks, doors, gates and buildings ... Lack of railroad common sense in the design phase may kill or maim a trainman ... They really don't like you when you take their shiny new facility out of service before it even opens.)

Was that track storage capacity with the slack run in or out?

How much tail room do you have? 

With grain loaders, are you figuring-in room for a switcher and someplace to get it out of the way? carmover (& set-off)? joe-Bob AgriDummy and his tractor?

 

Thank you, track storage capacity was with the slack run out. I'm not writting about any particular industry or model layout. With grain loader, maybe I need to find some prototype example.

 

[diningcar]

Any track curviture envolved; and if so does the track have to fit  to rectangular buildings doors.

[jeffhergert]

There was a private car repair facility in Council Bluffs, since closed, that didn't seem to worry about track capacity.  I would often saw where they had shoved a car off the end of their tracks.

When they closed, they tore down most of the buildings.  Including part of what once was the UP Transfer station built in the 1860/70s.

Jeff