Elevation and grades

An open forum to discuss all aspects of the New Haven Railroad.
rsullivan
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Joined: 14 Dec 2016, 20:36

12 Sep 2017, 15:31 #21

Mr. Statkowski. How does the degree of the curve figure into the tractive effort of the locomotives to calculate the total tractive effort of all the assigned locomotives for that particular train? Does a sharper curve entering a grade require more tractive effort than the same curve during the grade? Or, does the grade determine speed for the curve and not tractive effort for the grade only? But, if going to slow due to the curve, does the train require more tractive power to overcome the grade because of the slower speed? That is why I am so happy you and all the other railroaders participate in the Forum and always jump in to help out with these quandaries.
Richard H. Sullivan, Jr.  member #3967
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Statkowski
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Joined: 05 Mar 2003, 09:39

12 Sep 2017, 15:50 #22

Both grade and curve figure into tractive effort required.  With grades you're fighting gravity, and with curves you're fighting wheel resistance.  The sharper the curve, the more the sides of the wheels are going to rub against the rail.  Combine the two and you're just making life more difficult for train operations.  Speed on the curve is also limited by centrifugal force.  Go too fast and the train will tip over (can we say Jenkins Curve?).  From my home northward the rail line essentially runs downhill, along with the river going downstream, yet pushers were required in steam days not for the grades along the way, but for all the wheel resistance on the curves, of which there were numerous.  When they ran unit coal trains from a large mine just to the south of me to the eastern part of Pennsylvania, every so often they had to turn the entire train just to equalize wheel wear on the cars.  Apparently there were more curves in one direction than the other, or the curves going in one direction were more severe than those going in the other direction.  One normally would not notice such wheel wear on go-anywhere freight cars, except these were the same coal cars going over the same route, day after day, the it showed - the wheels on one side became more worn than those on the other side.  Turning all the cars on the wye solved the problem.

Regarding knowing the weight of the train and the grades en route, most railroads, when they received new engines, came out with tonnage charts showing the maximum tonnage allowed for one unit over selected portions of the line's route, and eastward ratings might well be different from westward ratings.  If more than one engine, tonnage ratings were cumulative.  For the New Haven, such ratings were shown in their Arranged Freight Service Symbol Books or in a separate publication.

For example, from Symbol Book No. 20, the following ratings applied for the Cedar Hill - Bay Ridge route:
Cedar Hill to Oak Point:  2,500 tons, both westward and eastward for all diesel-electric road engines except for the DERS-7s and DERS-8s.  For them it was 2,900 tons westward and 3,100 tons eastward.  For the EF-4s, it was 3,800 tons westward and 4,250 tons eastward.
Oak Point to Bay Ridge:   1,300 tons westward and 2,100 tons eastward for all diesel-electric road engines except for the DERS-7s and DERS-8s.  For them it was 1,700 tons westward and 2,600 tons eastward.  For the EF-4s, it was 2,300 tons westward and 3,500 tons eastward.

Clearly, the EF-4s could outpull anything else on the road.

There was a special note for the newer DERS-4/5/6s limiting train tonnage to 4,500 tons westward between Oak Point and Bay Ridge when three units were used.

Tonnage ratings were not included in Symbol Book No. 14, but seeing as how 14 and 20 are the only ones I have, I can't say when they started showing such in those books.  
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rsullivan
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Joined: 14 Dec 2016, 20:36

12 Sep 2017, 16:44 #23

Thanks Mr. Statkowski. So someone modeling a specific portion of the New Haven would need the Arranged Freight Service Symbol Book for that portion of the line to determine how many of which types of locomotives a train required based on the consist's tonnage for the Symbol Books that indicate the tonnage. For a short grade like the one at Lower Yard in Brdgeport, will just calculating the total grade resistance with that chart help determine the tonnage rating needed for the locomotive(s)? Or, is that figured into the Arranged Freight Service Symbol Book No. 20? This is really helping me out a real lot, and I appreciate it.
Richard H. Sullivan, Jr.  member #3967
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Statkowski
Member
Joined: 05 Mar 2003, 09:39

12 Sep 2017, 17:27 #24

If one were operating full size freight trains in a model railroading world, tonnage ratings might come into play, but we're not doing that.  We're running reduced size freight trains, where a 20-car road might well represent the prototype's 125-car train.  Methinks thou might be thinking too much into a problem that might not exist.

No, the short line from Bridgeport's Lower Yard up to the Main Line would not be listed on any tonnage rating chart.  The dispatcher wouldn't even concern himself with such operations, except where any movements entered or left the main line.  For local freight operations, one might limit the car count to ten, and hopefully your Atlas S-1 or S-2 would be able to handle it.  Remember, pulling capacity on a model engine is similar to, but not the same as the real thing.  In a compressed model railroad environment, you could get away with using a 6% grade - the prototype could not.

You're not reproducing the prototype in scale form, merely simulating it.

Of course, if you really, really want to go totally overboard, here's a book for you:  http://chestofbooks.com/finance/economi ... index.html
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NH746EJO
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Joined: 25 Nov 2007, 00:18

12 Sep 2017, 18:41 #25

SOME THOUGHTS

      Mr. Sullivan: Let me add a few thoughts on operations to what Mr. Statkowski wrote.  I worked for the Rock Island for a few months, mainly in the downtown Chicago offices but for a while outside as a yard clerk.  However, I wasn't there long enough to learn much so most of what I know is not from experience.
      Operations tend to follow a routine except when things go wrong which hopefully is not too often.  The New Haven printed booklets on engine assignments, engine tonnage ratings and ran most freights according to schedules so there was a basic operating plan known to everyone.  Even local freights had a regular leaving time and the fast freights such as The Speed Witch, The Maine Bullet, The Cannonball, The Round Up, etc. had connections to make at interchange points and generally promised shippers specific leaving and arrival times.  That was especially important with cargoes such fish, produce, trailers, etc.  
      A yardmaster usually had responsibility for seeing that an engine left with its tonnage rating.  Usually the same engine or class of engine was assigned to the symbol freights so a yard could make-up a train according to the engine's ability.  Also, the yardmaster would see that the fast symbol freights were given cars with priority freight and were given less important cars only to fill out a train.  The "tonnage freight" not requiring fast movement such as coal, lumber, wool, grain, pig iron, etc. went in slower trains.
     The tonnage ratings for engines were relatively complex.  The tonnage rating was generally given in terms of slow freight but there were specific adjustments according to the importance of the train and weather conditions.  For example, The Speed Witch locomotive would be given a lower tonnage rating then a "tonnage train", so that it could maintain a high speed.  The rating would be further reduced in cold weather because of cold friction bearings on the cars.
        Also, consider that tonnage ratings were not given in actual tons -- ratings were in adjusted tons which the New Haven called equated ratings.  This was because a loaded car rolls better than a light empty.  Therefore, a train of empties of a given tonnage would require more power than a train of loaded cars.  The New Haven adjusted the engine's rating by assuming each car weighed 50 tons. If a 1500 ton train had 35 cars rather than the 30 it was assumed it should have if they each weighed 50 tons, it was considered that some were empties so the engine rating was reduced by 12 tons for each car over 30 because the empties required more power.  If the train had less than the 30 assumed in the rating, the rating would be adjusted upward by a specified amount because the heavy cars required less power.  (You may have to think hard about "adjusted" tons.)  In practice I think the process was easier and less precise than the engine rating rules required.
       Conductors and yard clerks would enter the weights of each car in a train in "Wheel Reports".  In theory someone might be called on the carpet if a fast train stalled  or priority cars failed connections because tonnage rules were not followed but I suspect rules were not followed exactly.  I still remember one night in Blue Island outside Chicago where as a yard clerk I needed to tack a destination tag on each car of an arriving fast freight, not an easy job using a lantern and searching through dozens of cards .  The fast freight left well before I got every card tacked  -- I'm sure they sorted it out when it got into Chicago. 
        I also wonder how accurate tonnage calculations were.  Not all cars are weighed.  While in Chicago, I was pressed into service weighing some cars using a balancing scale (long arm and moving weights).  I wonder how accurate I was in balancing that scale especially since I was being urged to do it as fast as possible.  Not only that but often I could barely read the light weight lettering on the car sides so wonder if I got the load weight right.
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DBrion
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Joined: 21 Jun 2006, 05:52

12 Sep 2017, 22:03 #26

Mr. Sullivan, another book on prototypical railroading that might interest you is Elements of Railroad Engineering, by William G. Raymond, John Wiley & Sons, NY (1947).  Some of its lessons were applied by my model RR club when it came to modeling realistic bridges.  As Mr. Statkowski stated, you want your model RR to represent, not replicate, the prototype in miniature scale ... but it must be constructed per engineered practice.

With regards to grades and curves, many of the western RRs employed cuts and fills, and bored miles of tunnels, to level out their ROW’s as much as feasible.  It was a matter of first capital costs vs. everlasting operating costs.
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rsullivan
Member
Joined: 14 Dec 2016, 20:36

12 Sep 2017, 22:05 #27

Thanks again Mr. NJ746EJO and Mr. Statkowski. Does this sound like a correct by New Haven rules for Oak Point Yard? Three operators use switchers to empty and load six car floats. Two operators pickup new cars off the car floats and first weigh each car then place them on one of the three receiving tracks. NYCRR switcher brings cars through Port Morris Tunnel and either cuts off the string of cars and backs onto the lead to the NYC&HRR Yard and a NH switcher takes the cars for weighing and placement on the receiving tracks, or the NYCRR switcher places them on the NYC&HRR Yard (I have the name written down in several plces but don't recall it) receiving track. Two operators use the destinations to make up the trains in blocks on the four departure tracks, and the yardmaster orders the correct number of locomotives for each train based on destination, tonnage, and the number of empty cars. For every 15 empty cars one additional locomotive. This would require handling the car cards for each one, noting the empty or load and weight, and destination, and blocking a train, then the yardmaster receiving all the cards and determining the number of locomotives by types available at Oak Point Motor Storage. I'm trying to imagine how I can set up my first part of the layout for operating to make both interesting and as close to New Haven practices as possible. It will be my way of keeping the spirit of the New Haven alive.
Richard H. Sullivan, Jr.  member #3967
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Statkowski
Member
Joined: 05 Mar 2003, 09:39

13 Sep 2017, 00:43 #28

Although Oak Point had eight float bridges, unless they were swamped with rush hour traffic I don't think they would have been loading or offloading six carfloats at any one time.  Four maybe, and two switcher crews would be more than enough to take care of that.  Each carfloat, which generally ran in pairs when handled by a tug, would hold maybe 17 40-foot cars, or less, depending on the cars' weights.  A switcher would shuffle strings of cars between the Float Yard and One Yard, coming out onto Track 6 at S.S. 4 from Four Bridge East or Along the Wall tracks, then going back into the yard on One Yard track.  Most freight yards had a yard lead to avoid fouling the main line; Oak Point's yard lead was the main line (Track 6).

As for weighing each and every car going on to or off of the carfloat, this was not done.  Arriving carfloat cars had already been weighed somewhere, departing empty cars really didn't need weighing, and the bulk of the loaded departing cars probably had already been weighed unless they had been loaded locally.  Depending on the tariff, and the customer, sometimes cars travelled with an agreed-upon weight (this shipper said the cargo weighed so much, and the railroad accepted that as Gospel for billing purposes).  So, some cars were weighed, some weren't.

As for the interchange with the New York Central at Port Morris, I can't honestly say if the Central pushed the cars up onto the interchange track or pulled them on, pinning ahead, and then running around the string to get back to home rails.
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rsullivan
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Joined: 14 Dec 2016, 20:36

13 Sep 2017, 02:37 #29

Thank you M. Statkowski for the information on the scale house at Oak Point Yard. From the scale house location, I thought it had to do with the yard just west of the Float Yard. I had scaled down my main from six to four tracks and added two yard leads to S.S. 4. I also scaled back from eight to six car floats piers with six car floats and three transfers permanently attached. I had thrown in the weighing as a function, but will drop it now. The NYCRR had a yard lead connecting to Oak Point Yard just south of S.S. 3 (Bungay Tower) which I'm going to include with the NYC&HRR Yard scaled back and closer to Oak Point Yard. I'm also putting third rail along a portion of Oak Point Yard even though it wasn't really there so the NYCRR S-1 switcher can bring a cut out of Port Morris Tunnel and back it into the NYC&HRR Yard. I'm trying to squeeze it into an area 28' by 14' so I have to condense everything somewhat. Keeping it on thread topic, at S.S. 3, the NYCRR track to Port Morris Tunnel will be going downgrade between 1% to 1.25% for about 3.5 feet. At the same time, the four main line tracks will start the uphill grade at about the same amount for the beginning of the approach to Hell Gate, while one or two ground level tracks will continue between S.S. 3 and the mainline for the westend yard leads. All three will go to staging and passenger train turn around tracks. All of the yard trackage will be about 30 feet above sea level. After passing S.S. 4, the main line will start a slow uphill grade. That is my attempt at making a scaled back operating version of the Oak Point Yard in my limited space.
Richard H. Sullivan, Jr.  member #3967
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NH746EJO
Member
Joined: 25 Nov 2007, 00:18

13 Sep 2017, 15:06 #30

WEIGHING, ETC.

To expand slightly what Mr. Statkowski wrote about weighing cars, the rule was (1928) -- all cars originated and received must be weighed EXCEPT those covered by shippers weight agreements, when classification or tariffs provide specific weights, when revenue is computed on other than a weight basis, or cars are received with waybills showing weighing by the previous carrier.  In other words, the presence of a scale in a yard doesn't mean all cars will be weighed.  At Oak Point nearly all cars would have been previously weighed.  However, on a model of Oak Point you might add some interest by weighing a few cars that are exceptions, maybe a car received from a nearby industry not previously weighed.

One book that every New Haven fan should have is FREIGHT TERMINALS AND TRAINS.  It was written by the New Haven's General Manager John A. Droege and has 572 pages of interesting information.  I have the second edition printed in 1925 (McGraw-Hill) but I recall that Kalmbach published a reprint not many years ago.  There is a chapter on water-front terminals but Oak Point or Harlem River are not covered.

Regarding modelling the yard at a height of 30 feet, my personal view is that modelers tend to make their wharves too high (you would think they model the Bay of Fundy).  My profile shows the track area to be no more than 10 feet high or at the mean high water level. (0.0 is mean high water at New Haven, vertical numbers are grades in feet per mile.)
IMG-002.jpg
I'm going to scan some freight schedule data but I'll post it as a new topic since I think the thread drift has gone far enough here.
Last edited by NH746EJO on 13 Sep 2017, 15:27, edited 2 times in total.
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