[SergentEng] Is there a maximum train length?

Tim L

Ok, lunch done. I found what Frank had said on Scarpia's Trains website. (link out of courtesy).

I don't think anyone's actually tried a failure test by loading up
a coupler attached to a force gauge. It would be interesting.



---- Begin what Frank said ----
Seventy cars that weigh 3 oz would need about [70 cars X 3 oz/car X 0.01) =
] 2.1 oz of pull on straight and level track. That will require one average
HO diesel to pull it. This isn't even starting to stress the couplers. No

Seventy cars that weight 3 oz going around a reasonable curve, and up a 3%
grade will need about [70 cars X 3 oz/car X (0.01 + 0.02 + 0.03) = ] 8.4 oz
of pull. That's about 3 decent engines to pull it. Again, we aren't
stressing the couplers at all.

Ten average diesels all pulling together will against a nail driven in the
middle of the track will start spinning their wheels at about [(10 X 3.5 oz)
= ] 35 oz of pull. The couplers will feel that for sure, but this is still
no problem.

Twenty really good diesels all pulling against the nail can generate [(20 X
4.5 oz) = ] 90 oz of pull before the wheels start spinning. That's enough to
make me nervous, but still below any sort of failure point as long as the
couplers are assembled correctly.

Forty really good diesels all pulling against the nail will generate 180 oz
of drawbar pull. That's just silly.

I don't think 70 cars would be a problem at all.

Back when Railmodel Journal was still alive, they printed a Performance
Summary of locomotives in what seemed like every issue that was pretty
useful. It gave tractive force measurements for all sorts of locomotives.


---- End what Frank said ---

On 01/04/2016 11:29, Andrew Porter ihtsbih_2014@... [SergentEng] wrote:
I recently had the pleasure of operating on a layout with Sergent
Engineering couplers. I liked them enough that I thought I would give
the kits a try. I happen to belong to a modular model railroad club and
we sometimes run scale mile or longer trains. My questions: Is there a
maximum train length for these couplers, and has anyone had a coupler
open due to excessive force? From what I observed on the layout I
operated, it appears that there will be no issues.