Steepest Grade On The Monon

[George Lortz]

Ron,

It states in the 1964 Timetable that "The rating for multiple unit diesels will be obtained by adding together the rating for the individual units in the combination."

Is this reality or just a convenient way to do the calculation?  It seems that some power would be lost between units in the lash-up.

George L.

[George Lortz]

Here are two (poor) shots of a combination of diesels on the hill between Pekin and Borden.  They are headed by C628, #404 and trailed by C628, #407.  I cannot tell the number of the RS-2 between them.  The shots were taken in June, 1966.

George L.

[Steve Dolzall]

The RS-2 is most likely #23 since it had that odd extension on the steam generator stack. The lead C628 appears to have lost the clear lens on the nose mounted signal light.

Steve

[Ron Marquardt]

The RS2 between two C628's was standard power on through freights south of Lafayette.  They learned quickly that 3 C628's was too much power, and two wasn't quite enough.  They had to modify the air brake equipment for the RS2's to MU with the C628, but once that was done, the mixed consists preformed well together.  / Ron 

[Pete Pedigo]

George,

To prevent the loss of power of MU'd diesels the railroad kept lists of which engines were compatible to run together in MU.

The only way there should be a loss of power would be a dead engine, or an incompatible engine, meaning geared lower, or under horsepowered and being dragged along instead of keeping in sync.

any other comments from someone else more in the know that I ?

Pete

[Steve Dolzall]

According to the diagrams, the Monon RS-2's were built with a Westinghouse 6 DS brake schedule. The C420's, C628's, and U23B's models all had a 26L brake schedule. The Monon had to modify the RS-2's to be compatable with the brake schedule utilized on the newer road power. The RS-2's, the Centuries, and GE's all shared a 74:18 gear ratio so that was not an issue.

[Ron Marquardt]

Tractive effort (drawbar pull) was based on about 20% of locomotive weight at MCS (the mininum speed at which a locomotive could operate continuously without overheating the traction motors).  Mininum Continuous Speed varied somewhat with different types of locomotives, but generally it was between 10 mph and 12 mph, and that was the speed a train was projected to operate when it was at full tonnage on the ruling grade.  When different types of locomotives were MU'd, they would all be pulling at or near their MCS on a hard pull.  They didn't have to operate exactly the same because there was a fudge factor built in to the MCS figures to protect the traction motors, so it all worked rather well.

If you had three locomotives with different tonnage ratings, say 1500 tons, 2000 tons, and 2500 tons, and ran them in MU, they would pull the combined tonnage rating which would be 6000 tons.  It was weight on drivers at MCS, not horsepower, that determined how much a locomotive would pull, and it would pull its rating whether it was by itself or with others.  Horsepower came into the equation only when you figured how fast a locomotive would pull its rated tonnage over a hill, but not how much tonnage it would pull.  Tractive effort was dependent on locomotive weight, because once you lost adhesion, the amount of horsepower was irrelevant.

With modern locomotives, steerable trucks, and advanced wheel slip systems, the tractive effort is probably up around 25% to 30% of engine weight, maybe even higher.  Of course the final factor in how much tonnage you could pull on a hill was determined by the tensel strength of the knuckles, and that what why the Monon didn't usually run three C628's together.  Three 628's was too much power when loaded to full tonnage, so that's why they went to the C628-RS2-C628 combination as regular power on all their through freights.  / Ron

[Gene Remaly]

Ron:

Your comment about three 628 had too much horse power for the train draw bars. I'll buy that, but, didn't they also use an RS-2 in the middle to spread the engine weight out over light bridges and culverts ?

Question on tonnage---Did they use actual light weights or just figure a 40' box car weighed  "X"
tons ?
 
Also, loaded car weights were taken from bills of lading --- right

[Ron Marquardt]

Gene, I don't think the engine weight was ever an issue.  We operated the three unit consists for some time until they figured out why we were having train separations, and even later it wasn't all that unusual to have a couple of C628's in tow behind our regular consists.  They even ran three C628's down the French Lick branch on a number of occasions to get Southern coal trains.

One more thought about the three unit consists.  It wasn't the three units that was the problem.  It was the tonnage they wanted to pull with the three units that was the problem.  When they loaded three units down to full tonnage, the tractive effort at the crest of the hills exceeded the strength of the knuckles and we had separations.  To get the tractive effort down  to acceptable levels, they had to handle less tonnage, but that wasted power, so they started running the RS2's between two C628's.  At full tonnage, they were close to the limit of the knuckles, but within acceptable limits.   I also think it was a power availability issue.  Three units meant only three consists were available for through freight use, while using an RS2 meant that four consists were available plus one left over.  I think they bought the C628's for coal train service, and when that business never materialized, they were stuck with them and had to figure out the most efficient way to utilize them.

I don't know the answer to your question about lightweights.  Maybe someone on here with a clerical background can answer it.  They may have guesstimated it at 30 tons per car.  I really don't know.  I'll send Gordy Stevenson an email and see what I can find out.

The did get the loaded weight off the waybills, and that would include the lightweight when they weighed it.
 

[Rick Dreistadt]

As for weight of empty cars, the clerks just estimated it.  I believe in the 60's or 70's, they estimated empties(except auto racks) at about 25  tons.    That wasn't exact, but pretty close.  As best as I can remember, in actuality boxcars would be about 26-28 tons, and hoppers about 21 tons.   When we billed grain in boxcars at Clay City there was a place on the waybill towards the top for gross tonnage. If the grain was 50 tons, we would show 75 tons on the top of the waybill for gross tonnage. 
Rick

[Robert Wheeler]

There is a discussion of tonnage ratings etc, on pages 134-155 of the 2008 Tour Guidebook (Stone District).

Included are tonnage ratings for steam and diesel locomotives (Shops to Youngtown plus B&B)( the ratings for diesels are estimated for the B&B);

Weights for empty cars and locomotives from employ timetables in the 1920's and last employee timetables are shown.

[Tim T Swan]

Wasn't the "LT WT" printed on the side of each freight car?

Re: those nice photos of the C628-RS2-C628 consist climbing the Knobs, the first car following is a tank car.  I've always been told tankers or any other Hazmat car must be 6 or more cars away from the engine or caboose.  Is this just another model railroaders' myth?

[Rick Dreistadt]

Tim, as far as tank cars, it depends on whether they are placarded dangerous or not.  This tank car could be hauling soybean oil, for instance, and if not placarded, it's OK behind the engine.  And yes, the cars have their weight stenciled on the side.  In this computerized age, that weight would show up on the trains consist, but in the pencil pushing days getting the weight off the side of each car would have been labor intensive but each class of cars weighed approximately the same anyway so estimating the weight was pretty accurate. 
Rick