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Articulated spine or well cars in even multiples?

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Articulated spine or well cars in even multiples?
Posted by cefinkjr on Thursday, June 13, 2013 12:29 AM

Are there any articulated spine or well cars with an even number of units? 

According to an article I just read on this site, there have been some 1200 pairs of 89' flats articulated to carry three trailers (with one over the middle truck).  But are there any articulated spine or well cars with an even number of units?  I've seen lots of 3-unit and 5-unit cars but never any with 2 or 4 units.

Chuck
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Posted by tdmidget on Thursday, June 13, 2013 12:32 AM

Take a deep breath and think about that question. It's not even a question. It's just dumb. How in the hell could that happen? you could not have less than 3 wells, right? So the more units you can have with one car number, the more revenue per car.  Pretty easy to see that when you go to the bank to finance it, the more revenue per car, the more likely you are to get a loan..

Now look at your return on investment. 4 trucks will haul 3 wells. That's 3/4 per well or .75 wells per truck. 4 wells is 4/5 trucks or .8 wells per truck..  5 wells is 5/6 trucks or .83 wells per truck. Obviously more wells means more capacity per truck, which is the most expensive part of the car.

Shouldn't be too had to understand.

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Posted by cefinkjr on Thursday, June 13, 2013 12:59 AM

tdmidget

Take a deep breath and think about that question. It's not even a question. It's just dumb. How in the hell could that happen?

Let me draw you a picture.  Where ______ is a spine or well unit and oo is a truck, a typical 3-unit car would look like this:

________ ______ ______

oo          oo          oo       oo

 

and a 4-unit car would be:

________ ________ ________ ________

oo          oo             oo             oo            oo

Chuck
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Posted by cefinkjr on Thursday, June 13, 2013 2:05 AM

tdmidget

Take a deep breath and think about that question. It's not even a question. It's just dumb. How in the hell could that happen? you could not have less than 3 wells, right? So the more units you can have with one car number, the more revenue per car.  Pretty easy to see that when you go to the bank to finance it, the more revenue per car, the more likely you are to get a loan..

Now look at your return on investment. 4 trucks will haul 3 wells. That's 3/4 per well or .75 wells per truck. 4 wells is 4/5 trucks or .8 wells per truck..  5 wells is 5/6 trucks or .83 wells per truck. Obviously more wells means more capacity per truck, which is the most expensive part of the car.

Shouldn't be too had to understand.

 

Your modified post asks rhetorically if there could be less than 3 wells.  There certainly could be only 2 wells riding on 3 trucks; I just haven't seen any.  And, of course, one well on two trucks would not be articulated.

Following the logic of the second paragraph of your modified post, a 10-well car (with 9 trucks) would be .91 wells per truck.  The wells per truck ratio that you propose will obviously increase (improve???) proportionally to the number of wells; approaching but never reaching 1.

But my question was not about the economics or ROI of articulated cars.  I only asked if there are any with an even number of spines or wells.

Chuck
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Posted by Mookie on Thursday, June 13, 2013 10:10 AM

Boy - we had a derail before we even got started!

I was enjoying the question until...

I, too, have noticed that spines and wells come in odd numbers.  Why?  And, thank you.

 

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Posted by carnej1 on Thursday, June 13, 2013 11:18 AM

cefinkjr

tdmidget

Take a deep breath and think about that question. It's not even a question. It's just dumb. How in the hell could that happen?

Let me draw you a picture.  Where ______ is a spine or well unit and oo is a truck, a typical 3-unit car would look like this:

________ ______ ______

oo          oo          oo       oo

 

and a 4-unit car would be:

________ ________ ________ ________

oo          oo             oo             oo            oo

While I agree that this discussion is getting a little too "chippy" TDM did not try to say that a 4 well stack car was impossible to build. If you carefully re-read the post he is referring to the efficient distribution of weight per truck in an articulated car set, and he explained why an "odd numbered" set offers better weight distribution than an "even numbered" set would would..

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Posted by Mookie on Thursday, June 13, 2013 11:56 AM

Evidently you are more well educated than I am because I didn't get anything like that from the reply to the post.  And I initially read the post 3 times. 

But I think you explained what we wanted so we can understand. 

Thank you.

 

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Posted by Paul of Covington on Thursday, June 13, 2013 11:58 AM

   Seems to me that some of us are asking one question, and others are answering a different question.

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Posted by greyhounds on Thursday, June 13, 2013 12:15 PM

Some of the original articulated intermodal cars, the Santa Fe "Fuel Foilers", were built and operated in groups of 10 articulated spine platforms.

As with many business decisions, the number of platforms/wells involves a trade off.  The more platforms/wells on a car the less flexibility there is. You end up dragging more empty spaces around.   The current preferred well car now has three wells - which seems to be the optimum balance between efficiency and flexibility.   At least for now.

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Posted by oltmannd on Thursday, June 13, 2013 12:26 PM

greyhounds

Some of the original articulated intermodal cars, the Santa Fe "Fuel Foilers", were built and operated in groups of 10 articulated spine platforms.

As with many business decisions, the number of platforms/wells involves a trade off.  The more platforms/wells on a car the less flexibility there is. You end up dragging more empty spaces around.   The current preferred well car now has three wells - which seems to be the optimum balance between efficiency and flexibility.   At least for now.

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Posted by edblysard on Thursday, June 13, 2013 12:37 PM

Keep in mind each additional multiple boogie adds maintenance cost, and the opportunity for something to break.

While these things are not all that complicated, they do require periodic maintenance, so which would you rather have, 3 wells and 6 boxes or 5 wells and 10 boxes to deal with if you have to repair something, or 4/6/8 cars and corresponding number of containers out of service.?

Say you had a 6 well car, and the set has an issue, that’s 12 containers that won’t make their ship or final destination on time, and that’s a lot of money sitting still, not a good idea.

And after a certain number of wells riding on joint boogies, you get close to the limit where string line derailment becomes more common, (remember, you have to have some slack action and the ability of a coupler to swing wide, whereas the boogie has no slack and no swing.) which is one of the reasons that the AutoMax articulated auto racks are only in 2 car configurations, you could do a 3 or 4 car set, but that would limit the routes the cars could travel based on the curves.

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Posted by DTomajko on Thursday, June 13, 2013 1:12 PM

I work at the Pittsburgh Terminal & have to admit that I've never seen well or spine cars with an even number of platforms. I have noticed that the 40ft wells are commonly in 5 unit sets & the 53ft cars are usually in 3 unit sets. Spine cars are common in both 3 &5 unit sets. I think the overall length of the car influences the number of platforms,(a 5-unit  car is around 300ft long). I can still remember when the Sante Fe 10-packs were split into 5-unit sets,they were easy to spot due to all the hitches faced the same way,(cars built as 5-packs have 1 hitch one way & 4 the opposite way). Have you also noticed that TTX has been stretching 48ft spine cars into 53's for about 3 years now? They don't even bother to paint the whole car, just the added section, with a 5 added to the origional number.

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Posted by CShaveRR on Thursday, June 13, 2013 5:19 PM

I was thinking that I remembered some drawbar-connected TTX well cars with four platforms (eight trucks), but I can't check it out at the moment.

My thoughts had been that there might be some reason to keep cars to an even number of trucks, but there are a number of articulated auto racks the put the lie to that one.  Also, don't forget those two-unit articulated spine cars for carrying trash containers on each of their 40-foot sections.  Those have three trucks, also.

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Posted by jeffhergert on Thursday, June 13, 2013 6:00 PM

CShaveRR

I was thinking that I remembered some drawbar-connected TTX well cars with four platforms (eight trucks), but I can't check it out at the moment.

You thought right.  Also some drawbar connected (not articulated) well cars in three and five platform configurations according to a diagram chart on how to figure the number of operative brakes on multi-platform cars.  Both articulated and drawbar connected. 

Those paired 89' flats for three trailers, I don't think they are articulated either.  I think they are two cars drawbar connected.

Jeff

 

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Posted by cefinkjr on Thursday, June 13, 2013 7:16 PM

greyhounds

Some of the original articulated intermodal cars, the Santa Fe "Fuel Foilers", were built and operated in groups of 10 articulated spine platforms.

I had thought of those, but my only memory of them was having seen them offered as HO scale models and didn't know if the models were accurate or not.

I understand from another post in this thread that they have been split into 5-unit cars.  I can think of several reasons why that might have been done.

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Posted by timz on Thursday, June 13, 2013 8:32 PM

carnej1
he explained why an "odd numbered" set offers better weight distribution than an "even numbered" set would

He tried to explain it -- didn't succeed.

Like they said, SFe's 188 and 881 trains often? always? consisted of ten ten-platform piggyback cars circa 1981. Before that, weren't their prototype cars six-platform?

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Posted by jrbernier on Friday, June 14, 2013 4:12 PM

timz

carnej1
he explained why an "odd numbered" set offers better weight distribution than an "even numbered" set would

He tried to explain it -- didn't succeed.

Like they said, SFe's 188 and 881 trains often? always? consisted of ten ten-platform piggyback cars circa 1981. Before that, weren't their prototype cars six-platform?

  IIRC, the initial test was done with a '6 Pack' configuration, but ATSF went to a 10-Pack with the production order of cars.

Jim

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Posted by carknocker1 on Friday, June 14, 2013 5:44 PM

2 well and 4 well cars are all draw bar cars

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Posted by ericsp on Saturday, June 15, 2013 11:43 PM
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Posted by MidlandMike on Sunday, June 16, 2013 8:41 PM

ericsp

These cars were built 30 years ago.  Did they stay in that configuration?

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Posted by Dick Dawson on Monday, June 17, 2013 5:07 PM

Well almost.  We built a single prototype 4-unit COFC spine car at Berwick Forge & Fabricating and FreightCar America has built a number of 2-unit spine cars to carry short garbage containers with two stacked containers over the end trucks and one container at the inboard end of each unit for a total of 6 containers. 

Most other articulated cars (not drawbar-connected) have an odd number of units because this results in an even number of trucks (the number of units plus one).  The benefit of an even number of trucks is that you have two truck-mounted brake systems for every air brake control valve.  The AAR also requires that hand brakes operate on at least half the trucks of the car so, again, having an even n umber of trucks is beneficial.  This requirement was not in effect when the AT&SF 10-Pack cars were built.  Even the relatively small number of spine cars with body-mounted brake rigging benefit from having one brake cylinder and slack adjuster for every pair of trucks.  This is not a consideration with drawbar-connected well cars, which have self-contained brake systems with one control valve, two truck-mounted brake systems and one hand brake on each unit. 

The choice between an articulated car with a large number of units versus one with fewer units is a trade-off between the greater efficiency of a car with more units over which to distribute the cost and weight of the "extra" truck, and the greater operational flexibility of a car with fewer units.  TTX is no longer stretching 48' wells to 53', but continues to cut down 48' units to 40'.  The cut-down 40' cars, as well as the articulated cars built new with 40' wells, are 5-unit, whereas the articulated 53' cars are built with three units.  The reason for moving all well cars to 40' or 53' wells is that COFC traffic has settled into two different operations, 40' (and 20') international containers from the coastal ports and 53' domestic containers competing with 53' trailers. 

 

Dick Dawson - retired TTC Chief Engineer and Director Freight Car Engineering at Berwick Forge & Fabricating

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Posted by operator on Monday, June 17, 2013 5:24 PM

There are two body articulated auto racks.  A popular reporting initial for some of them is BTTX but I've seen many others as well.  However I've never seen any which weren't auto racks, no spines or wells.  Speaking as one who spent more than half of a 40 year career designing hump yard control software, even bodied cars are the only ones to have an odd number of trucks.  Single cars and 3 and 5 platform articulateds all have an even number of trucks.  The wheel counter truck detection software I've worked on for several employers all relied on having an even number of trucks per car and special software had to be written to correctly detect and support the two bodied auto racks as a special case.  The result however was code which was more sensitive to wheel counter errors than for "normal" even trucked cars.

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Posted by cefinkjr on Monday, June 17, 2013 11:01 PM

Dick Dawson

Well almost.  We built a single prototype 4-unit COFC spine car at Berwick Forge & Fabricating and FreightCar America has built a number of 2-unit spine cars to carry short garbage containers with two stacked containers over the end trucks and one container at the inboard end of each unit for a total of 6 containers. 

Most other articulated cars (not drawbar-connected) have an odd number of units because this results in an even number of trucks (the number of units plus one).  The benefit of an even number of trucks is that you have two truck-mounted brake systems for every air brake control valve.  The AAR also requires that hand brakes operate on at least half the trucks of the car so, again, having an even n umber of trucks is beneficial.  This requirement was not in effect when the AT&SF 10-Pack cars were built.  Even the relatively small number of spine cars with body-mounted brake rigging benefit from having one brake cylinder and slack adjuster for every pair of trucks.  This is not a consideration with drawbar-connected well cars, which have self-contained brake systems with one control valve, two truck-mounted brake systems and one hand brake on each unit. 

The choice between an articulated car with a large number of units versus one with fewer units is a trade-off between the greater efficiency of a car with more units over which to distribute the cost and weight of the "extra" truck, and the greater operational flexibility of a car with fewer units.  TTX is no longer stretching 48' wells to 53', but continues to cut down 48' units to 40'.  The cut-down 40' cars, as well as the articulated cars built new with 40' wells, are 5-unit, whereas the articulated 53' cars are built with three units.  The reason for moving all well cars to 40' or 53' wells is that COFC traffic has settled into two different operations, 40' (and 20') international containers from the coastal ports and 53' domestic containers competing with 53' trailers. 

 

Dick Dawson - retired TTC Chief Engineer and Director Freight Car Engineering at Berwick Forge & Fabricating

Thanks for the informative post, Dick.  You answered my question ('even numbers of articulated units in any kind of freight car are relatively rare') and told us why.

Bow 

 

Chuck
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Posted by ericsp on Tuesday, June 18, 2013 12:17 AM

MidlandMike

ericsp

These cars were built 30 years ago.  Did they stay in that configuration?

Judging by the scarcity of photographs, I would guess they didn't stick around for long.

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