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Model Railroading > Vertical Curves?


Date: 03/23/20 20:07
Vertical Curves?
Author: wabash2800

For fun I'm working on a bedroom-sized trackplan unrelated to my current basement layout. Anyway, it is a shortline with small locos for power and very short trains (6 to 8 cars max) with no cabooses, ala Winona Rwy in indiana or the Claremont and Concord in New Hampshire. Among many other features, a couple of the things I'd like to model are "hog back" grades on the mainline and challenging grades in industrial trackage.

I have grades on my basement layout with long trains and 2% grades, but this plan is a totally different animal, and these items would be for effect, i.e, to emulate low budget engineering or challenges in industrial trackage. For those not familiar with Hog Back Grades, picture the track sagging up and down, viewable by the naked eye, with something that looks like the exagerated perspective from a telephoto lens. Also, sometimes, if a shortline had been an interurban before switching over to internal combustion power for freight service, the trackwork could a bit challenging. That's because it was designed for interurbans with more power (electric) and the ability to manuever sharp curves and city trackage. And often, street trackage would follow streets with an undulating profile.

I'm wondering what I can get away with in HO.  I don't know if back EMF in DCC would help, but I could see an issue with even a short a train slowing down and speeding up unnaturaly with a preciptous undulating profile. Of course, another issue would be grades affecting the number of cars a small loco could pull. And also, too sharp of vertical curves might affect the couplers on the cars.

Has anyone here attempted such dramatic effects or seen such on the Internet?

Victor A. Baird
http://www.erstwhilepublications.com
 



Edited 4 time(s). Last edit at 03/23/20 20:25 by wabash2800.



Date: 03/23/20 20:18
Re: Vertical Curves?
Author: DKay

I seem to recall our expert CNW modeler (Dennis) has some neat hog back effects on his amazing layout.Sure to be some fine pics in the T/O archive.
Regards,DK



Date: 03/23/20 20:30
Re: Vertical Curves?
Author: wabash2800

Thanks for the reply DKay. I see that Dennis' post was here in reply to a similar question.

https://www.trainorders.com/discussion/read.php?3,1633286,1633331#msg-1633331


Victor A. Baird
http://www.erstwhilepublications.com



Edited 2 time(s). Last edit at 03/23/20 21:14 by wabash2800.



Date: 03/24/20 09:26
Re: Vertical Curves?
Author: jridge

I remember the old Atlas over and under figure 8 pier set. I put that together and the vertical curves caused constant uncoupling problems.  But that was a long time ago and my coupler heights probably weren't consistent.



Date: 03/24/20 09:39
Re: Vertical Curves?
Author: toledopatch

jridge Wrote:
-------------------------------------------------------
> I remember the old Atlas over and under figure 8
> pier set. I put that together and the vertical
> curves caused constant uncoupling problems.  But
> that was a long time ago and my coupler heights
> probably weren't consistent.

Having track hanging in the air between piers with no support structure wasn't exactly optimal for preventing vertical curvature.
 



Date: 03/24/20 10:35
Re: Vertical Curves?
Author: bigmc83

I believe inCHI has some excellent industrial trackage that captures the unevenness of old, rarely travelled trackage.  

-Sean



Date: 03/24/20 12:46
Re: Vertical Curves?
Author: Jeff_Johnston

The start of a vertical curve can be a bugger, but it can work fine if you take your time and engineer the subroadbed as smoothly and carefully as possible. The photo shows a place on our HO scale Sugar Pine Lumber Company layout where the 3-percent-plus branchline to the woods leaves the mainline at Central Camp. The #6 switch is at the right edge of the photo under the third log car. The mainline, foreground and exiting at lower left, is just under a 1-percent grade down to offline staging, so we have two grades meeting at the switch that's on a level piece of roadbed. Both locomotive types that will be using this branch, the Alco 2-8-2T (shown) and the big Alco Minarets type 2-10-2T, navigate this vertical curve just fine, and the 40-foot log flats remain coupled with no problems, even using Kadee #58s. 

To ease into the grade, notice the saw kerfs cut into the 1/2-inch plywood subroadbed at right. This allowed the plywood to flex somewhat more easily immediately adjacent to the switch while avoiding any sharp "curves" so to speak. The same kerfs were used on the logging branch side, they just aren't visible in this photo. The 1/2-inch Homasote roadbed was flexible enough to accommodate the vertical curves without any saw kerfs.

Granted, this type of operation is a lot easier with shorter equipment with less end overhang to cause coupler misalignment, but even modern longer rolling stock can move through such an area if it's designed and built with care. 

Good luck!

Jeff Johnston
trainvideosandparts.com




Date: 03/24/20 13:10
Re: Vertical Curves?
Author: ChrisCampi

Well done Jeff. Nicely engineered with th kerfs. Notice the couplers between the loco and the flat car. Looks like the loco has a standard size couple which is saving the day here.

I have a vertical curve on my layout that doesn't like longer cars and McHenry couplers, but Kadee #158's do well. Maybe do to the flex and slipper plastic of the McHenry's.



Date: 03/24/20 14:01
Re: Vertical Curves?
Author: Jeff_Johnston

Thank you for the kind words!

This locomotive was finished long before the #58s were available, and will be retrofitted with 58s and adjusted as appropriate; that said, a certain amount of vertical offset is to be expected on undulating track. Our trackwork is such that we can operate equipment with 58s and have no offset-related uncouplings because we pay attention to coupler heights and track profiles. We spend a lot of time fiddling around with shimming different track levels and such, kind of a PITA but worth it in the long run.

The switch in the photo is at the flat grade Homasote level at left, and drops down 1/2 inch to the next level for the Pinedale mill loading tracks at right. The switch is in the middle of the grade, certainly not ideal but it works. Took a lot of experimenting with different cardstock shim thicknesses, making for smooth vertical curves and "ramps" up and down, to get this area to accommodate the 40- and 50-foot boxcars that typically will serve the mill. Thankfully the ugly shims etc will all be ballasted over or hidden by groundcover.

Jeff




Date: 03/24/20 16:29
Re: Vertical Curves?
Author: CNW

DKay Wrote:
-------------------------------------------------------
> I seem to recall our expert CNW modeler (Dennis)
> has some neat hog back effects on his amazing
> layout.Sure to be some fine pics in the T/O
> archive.
> Regards,DK

Here are a few pics of my sag.  The grade is around 1.25% maximum.  The sub-roadbed was built using two clear pine 8-foot 1x4s. 

Dennis








Date: 03/25/20 06:22
Re: Vertical Curves?
Author: kevink

CNW Wrote:
-------------------------------------------------------
> Here are a few pics of my sag.  The grade is
> around 1.25% maximum.  The sub-roadbed was built
> using two clear pine 8-foot 1x4s. 
>
> Dennis

Whoa, that second image is awesome! Fantastic modelling all around!



Date: 03/25/20 09:26
Re: Vertical Curves?
Author: tomstp

Wow, pictures 2-3 certainly capture real railroads rolling  right of way.  Really a fantastic modeling job.



Edited 1 time(s). Last edit at 03/25/20 09:27 by tomstp.



Date: 03/25/20 12:00
Re: Vertical Curves?
Author: wabash2800

Thanks for the replies and photos. Now, I wonder why some class one mainlines have such profiles. Was this a matter of economics when building the railroad in that money was not spent on more fill? To be sure, grades are a normal thing, but Hog Backs that are much more pronounced and shorter are what I am questioning. I'm not interested in assumptions. I believe there were some class one routes that were notorious for this phenomenon such as at least one line on the SAL and an alternate route on the southern part of the IC. I seem to recall the former had caboose crews taking serious precautions to protect them from slack action.

Victor A. Baird
http://www.erstwhilepublications.com



Edited 3 time(s). Last edit at 03/25/20 12:48 by wabash2800.



Date: 03/25/20 16:26
Re: Vertical Curves?
Author: wabash2800

Here's the querry I put out on the Nostalgia Board with some replies:

https://www.trainorders.com/discussion/read.php?11,4983962

Victor A. Baird
http://www.erstwhilepublications.com



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