Sn2 Modeler

In a an earlier post, I tested how many cars an Sn2 Forney could pull.  Click here to see post and watch video.  In that post I showed how many cars an Sn2 Forney could pull on level track and hypothesized about how many a Forney might pull on 2% or 3% grades.  In my last post I proposed a new track plan that my friends responded to positively.  The plan calls for three decks and stiff grades (upward of 2% see chart at bottom of link) to get between them via a “nolix” design.  If I’m going to take this design seriously, I need to confirm that such grades will meet my operating goals.  So testing is required.

The weekly model railroading session just happened to be at my house on this week, so Phil and Paul helped me conduct some tests.  First step was to setup a grade.  We did this by putting the last two free-mo modules on a grade by shimming the feet of the legs.

Here is the setup. Can you tell the two modules are on grade? Roughly 2%

The legs were shimmed with 1/2″ boards. The far legs were remained on the ground, the intermediate legs got two boards (1″) and the near legs got four boards (2″) to establish a 2% grade over 8 feet.

Once the setup was made, we ran trains of cars up the grade and watched for slipping.  WW&F #7 handled 6-7 cars up a 1% grade, and then 4-5 cars up a 2% grade and 3 cars up a 3% grade.  Let me tell you we had 15+ minutes where I was scared, as I wrongly thought the 3% grade was 2%.  3 cars up a 2% grade was never going to be acceptable.

Later, we decided that not all cars were equal.  We thought weight was a significant contributor.  In the end, I dug out 7 HO Walthers cars that had HOn3 trucks on them (these has been used during ops on my previous layout…way back in 2005).  With these and the corrected 2% grade WW&F #7 was able to pull a 8 car train up the grade.  9 cars would be great success!

The following day I got curious and tested with one of the small 0-4-4T Forneys,  T&T SR&RL #7.  It was able to pull 7 of the cars up the grade.

T&T SR&RL #7 with 8 cars, ready to take on the grade, this missed but removing the last car resulted in success with a 7 car train.

After completing the test, I wondered if weight was the only factor.  So I did rolling tests to see how well the cars rolled.  The results were unexpected.  Many cars which I thought had good Kadee trucks on them did not roll well at all.

Free-rolling test. The cars came down the 2% grade from right, then rolled freely across two curved modules. When a car stopped, I placed off the rails next to where it stopped

As you can see from the test, some cars hardly rolled one foot, yet others rolled 6 feet.  So what is the difference?

Here are a few quick notes:

1. SR&RL Flat (on track) – Rolled 0″, weight 1.8 oz, KD trucks
2. SR&RL Pulp Rack (at front) – Rolled 1/2″, weight 2+ oz, KD trucks
3. SR&RL Box (behind) – Rolled 5″, weight 2.5+ oz, KD trucks
4. PRR Box – Rolled 8″, weight 1.6 oz, MDC trucks with brass wheelsets
5. Stark Box – Rolled 13″, weight 1.6 oz, MDC trucks with brass wheelsets
6. Tichy Flat – Rolled 29″, weight 0.8 oz, MDC trucks with nickle plated wheelsets
7. SR&RL Box – Rolled 36″, weight 2.5 oz, MDC trucks with nickle plated wheelsets
8. SR&RL coal – Rolled 62″, weight 2.5 oz, MDC trucks with nickle plated wheelsets
9. SR&RL flat – Rolled 67″, weight 2.5 oz, MDC trucks with nickle plated wheelsets
10. There was one SR&RL box with KD wheelsets that would not even roll down the 2% grade when I pushed it.

Observations:

• Weight is a factor, but not the only factor effecting locomotive pulling power.
• Not all trucks are the same.  The trucks and wheelsets effect the drag and likely limit loco pulling power.
• KD trucks are not the quality I need.
• The light weight cars all have MDC trucks, so were easier to pull because they were lighter and the trucks were more free-rolling than the MDC.

Blackstone trucks set the standard!

None of my cars have Blackstone trucks on them yet.  But I’ve been planning to put them on my passenger cars and cabooses and possibly some freight cars as stand in’s until I can build the Smokey Mountain Model Works trucks.  Being curious, I put one of the trucks on the tracks and let it roll.  It rolled freely for over 7 feet!  then rolled back 2 feet.  Yes, this truck rolled further than any other set of trucks with a car body (mass) on top.  The trucks roll so freely, they can be used to test level!  I plan to use a Blackstone truck to level my modules at the next setup.

Summary

• 2% grades will be acceptable if I use qood quality trucks and keep the cars light.  My plan has always been to minimize the grades from Farmington to Phillips so that I could run longer 8 car trains with a big forney and 10-12 car trains with a 2-6-0 or 2-6-2 or 2-8-0 loco.  Likewise from Strong to Kingfield, I’d like to be able to run 8-10 car trains.  However, north of Phillips to Rangeley and north of Kingfield to Bigelow, I’ve always planned to run shorted 5-7 car trains and require crews to double the hills when required (just like the prototype).
• Blackstone trucks are the GOLD standard.  All KD trucks will be replaced.  MDC trucks with nickle wheelsets may be remain.  David Hoffman made an order with NWSL to replace the MDC wheelsets.  I have a few of the Hoffman wheelsets so will test to determine if they are acceptable.
• I have SMMW truck kits and Tichy trucks that can be converted to a more “scale” Sn2 truck.  But if I’m not able to make them run smoothly as a MDC nickle plated truck, then they will not be used.  I’m more about operations than looks!
• I will set standards for truck rolling and car weight.  Only if both are met will I allow a car onto the layout (once built).
• I will have to set operating limits on how many cars can be pulled by locomotives between towns.  The locomotives will take excess wear if crews do not follow the rules.  I do not want to get drivers nickle plated every few years or be required to make new frames should the originals wear out…
• Onward!  This testing does not deter me from proceeding with Sn2.  Just the opposite, it makes me optimistic.