Thanks Guys, for the infomation on vertical curves, for a reminder I'm building a two level layout, and to eliminate the problem I lowered the top level slightly and by adding risers at the top of my grade.
I know my basement floor is not level. I've had to makes some adjustments to compensate.
Now what was this topic originally about?
Rio Grande. The Action Road - Focus 1977-1983
richhotrain Medina1128 If you have your layout in your basement, you'll find that the floor has a gentle slope to the drain in the center of the room. That's why having adjustable legs really works. A minor correction is in order. If you have your layout in your basement, the floor should have a gentle slope to the drain in the center of the room. When they poured my basement floor, they neglected to provide that gentle slope. My basement floor does not slope, and it is not perfectly level. There are dips and valleys all over the place. Rich
Medina1128 If you have your layout in your basement, you'll find that the floor has a gentle slope to the drain in the center of the room. That's why having adjustable legs really works.
If you have your layout in your basement, you'll find that the floor has a gentle slope to the drain in the center of the room. That's why having adjustable legs really works.
A minor correction is in order.
If you have your layout in your basement, the floor should have a gentle slope to the drain in the center of the room. When they poured my basement floor, they neglected to provide that gentle slope. My basement floor does not slope, and it is not perfectly level. There are dips and valleys all over the place.
Rich
Well, the adjustable legs would still work if your floor is not level. When adjusting the legs a beam level comes in handy to ensure your benchwork in level in each plane.
Marlon
See pictures of the Clinton-Golden Valley RR
richhotrainA minor correction is in order.
This is where one of those spinning laser levels is worth its cost. Mark the desired benchwork height, get the level aligned in different locations, measure the height. This plane of light is then a cutting or alignment guide for uprights (or for adjusting variable length legs) as you go.
When we did Studio C in the '70s we used the old Egyptian leveling trick. The footing forms were cat-food cans connected by aquarium tubing into which we poured leveling cement with acrylic bonding agent. Sealed to the rough concrete with the wax from toilet rings. The result was a bunch of footings at a perfect 'level' common height preserving the floor drainage. Some variant of this might be useful here.
Alton Junction
I glue and screw, using 1 1/2" drywall screws lengths of 1x4 into an L-shaped leg. I cut a length of 2x2 (about 6") and glue, clamp, and screw into the inside corners of the bottom of the leg cutting them flush from the end. Once the glue has dried, I drill a hole into the end of the leg. I use 1/4-24 T-nuts, so use the appropriate drill size drill bit to drill a hole into the 2x2. This is best done using a drill press to ensure perpendicular holes into the inserts. I screw 1 1/2"-2" carriage bolt to use to level the legs. The nice thing about carriage bolts is that they have a 1/4" head just below the rounded end of the bolts. I use a 1/4" ignition wrench to adjust the carriage bolt. When I attach the legs to the benchwork, I leave about 1/4" of a gap from the floor, so I have some adjustment room.
If you have your layout in your basement, you'll find that the floor has a gentle slope to the drain in the center of the room. That's why having adjustable legs really works. Since these pictures were taken I used a tapering jig on my table saw to cut the legs.
Most of my layout between towns is on grades, but I've not experienced any "humps" at the top of them.
I use 3/4" plywood for sub-roadbed, and fasten the bottom and top ends of the grade securely and level, then add a riser of suitable height, at the mid-point of the grade. Additional risers are added, again bisecting the distance between the ones already installed, until the entire grade is fairly constant...no humps, no sags, no problems.
In the photo below, the industrial sidetracks to the extreme left and right are level, while the main tracks to the left are rising both towards the camera and in the distance, somewhat slightly beyond the right side of the photo in the distance.The curvy track at the centre drops downward beyond the bottom of the photo, and is rising to the turnout, where it joins the mainline...
This grade, with multiple curves, is over 45' long, at a fairly constant 2.8%...
...and I have some up and down grades in opposite directions, too...
...this track is on a grade, too, but it's only .02%. The fact that it's on a curve does limit train length and weight, though...
Wayne
LastspikemikeYou do wonder why three two axle trucks were thought to be a better solution than two three axle trucks.
The "correct" answer, of course, was radial steering in C trucks, which EMD has now demonstrated works without determinate conjugated steering linkages. As this produces a truck with zero rigid wheelbase some external means of steering the truck frame becomes needed, but this is inherently provided (centerlessly to boot!) by the 'elephant foot' shear springs...
... which brings up the issue of vertical accommodation in a HTCR truck equipped locomotive. I haven't read of it being an issue; the primary spring travel alone ought to accommodate a significant vertical curvature without derailing -- although that's 'prototype' and not model geometry, there are some very sharp vertical transients within short distances that locomotives have to accommodate...
Overmod DrW two of the four prototypes had an articulated frame - but the articulation was vertical, not horizontal. The pic clearly shows the pivot point. The very reference from which you extracted your picture noted that the joint is for horizontal, not vertical accommodation. ... It will be interesting to see where these locomotives go with the Gotthard Base Tunnel open...
DrW two of the four prototypes had an articulated frame - but the articulation was vertical, not horizontal. The pic clearly shows the pivot point.
The very reference from which you extracted your picture noted that the joint is for horizontal, not vertical accommodation.
...
It will be interesting to see where these locomotives go with the Gotthard Base Tunnel open...
DrWtwo of the four prototypes had an articulated frame - but the articulation was vertical, not horizontal. The pic clearly shows the pivot point.
Only two locomotives (10601 and the pictured 10602) were built with the divided carbody. Softer secondary suspension allowed all the vertical-curve accommodation needed. All the production locomotives were built without the joint.
I do not want to side-track this very informative thread, but it is worth noting that also the prototype sometimes encountered this problem. When the Swiss Federal Railway (SBB-CFF-FFS) intended to purchase new 6-axle electric locomotives (with three 2-axle trucks) for the Gotthard main line, two of the four prototypes had an articulated frame - but the articulation was vertical, not horizontal. The pic clearly shows the pivot point.
richhotrain The word "hump" has taken on a special meaning in model railroading. I used the term hump in my own situation when I described my mainline track rising up to connect to the flat mainline track on an adjoining piece of plywood subroadbed set slighter higher. Whether it is truly a "hump" or an abrupt vertical connection, as in my case, the result is the same - - unintended uncouplings and possible derailments. Rich
The word "hump" has taken on a special meaning in model railroading. I used the term hump in my own situation when I described my mainline track rising up to connect to the flat mainline track on an adjoining piece of plywood subroadbed set slighter higher. Whether it is truly a "hump" or an abrupt vertical connection, as in my case, the result is the same - - unintended uncouplings and possible derailments.
Yeah, I see it the way Rich does. A hump is something you see at higher elevation than the mean elevation around you, and it would be a generally gradual rise over several yards in the 1/1 world. What we want to avoid is an abrupt grade change, but especially those more than about 0.5% because they can affect tracking and coupling, especially on curves. Naturally, on our layouts we have grades around 3% typically, often more severe. Such a change needs an even long, gradual, vertical curve. Unfortunately, this arrangement, required at both ends, serves to severely shorten the constant part of the grade between them. This will affect the attainment of a change in elevation.
Maybe kink is the word? A kink is an abrupt change in angle, whether in plane geometry or in linear terms, such as with rails. It can be in any plane.
Lastspikemike 1/4" plywood, particularly marine grade, is more than strong enough to support track and bends nicely to create grade transitions. Use marine grade if you include U boats in your fleet. The OP is using the very handy Woodland Scenics foam riser system which is easily scraped down for fairing purposes, no wood required. I have found that the 2% inclines are generally fine with no transition or easement of the entry to or top of the grade but filing down the top transition and adding a little filler to the bottom works and looks better. Do not fit rail joints at or near the top or bottom of the incline. Place turnouts only on the flat sections, either horizontal or sloped, not at or near the transition points.
1/4" plywood, particularly marine grade, is more than strong enough to support track and bends nicely to create grade transitions. Use marine grade if you include U boats in your fleet.
The OP is using the very handy Woodland Scenics foam riser system which is easily scraped down for fairing purposes, no wood required.
I have found that the 2% inclines are generally fine with no transition or easement of the entry to or top of the grade but filing down the top transition and adding a little filler to the bottom works and looks better.
Do not fit rail joints at or near the top or bottom of the incline. Place turnouts only on the flat sections, either horizontal or sloped, not at or near the transition points.
Simon
What I do for my HO scale layout is I raise the first foot and the last foot of any incline by an 1/8" then increase the rate usually about a 1/4" per 13" after the first foot and before the last foot.
I think what OP is describing is when the transition spot is too abrupt, (and perhaps the grade quite severe) it produces a fulcrum and a teeter-totter effect. Push down on the decline side and the flat side wants to rise. If the flat is connected to another track, a hump is going to be created. So shaving the abrupt joint to where there is no fulcrum should work.
But also, as others have noted, make the subroadbed out of one long piece and not several short pieces. Long enough to bridge the transistion points so that it wants to make a natural smooth curve. If you're bending the subroadbed down so far to where the track can't bend downwards as sharply, the grade may be too severe.
- Douglas
The little 'ding' in my head reading the original post was that his situation is exactly what Pruitt described: the track coming up the angled riser is not 'bent' to follow a transition, but continues to rise briefly before coming back to where it can be glued or otherwise secured on the flat. That overshoot is the 'hump'.
What I would do -- other advice from the experienced may vary -- is to make a template out of suitable material that follows the correct 'vertical curve' from a suitably long straight end for the riser around to a comparable straight end for the level. If you Surform or patch to where this gauge fits, you should have no trouble getting cork or flextrack to follow the vertical transition snugly. A convex version, perhaps with 'nonstick' facing in thin metal or plastic, could be used with a filler material (plaster, wood filler, putty, etc.) to give the smooth transition at the bottom of grades.
Perhaps this goes without saying but don't put any rail joints, soldered or otherwise, anywhere in the vertical curve or approach if you can avoid it. If you must, I'd advise figuring out some way to file or machine down the joint to follow the vertical curve precisely after the track is in.
SeeYou190I wonder where the happy medium is. I have always used 3/4" marine grade plywood for my subroadbed, and getting that stuff to bend takes effort and results in a final structure under stress. Perhaps I could use a section of a different material for the grade section. -Kevin
I have always used 3/4" marine grade plywood for my subroadbed, and getting that stuff to bend takes effort and results in a final structure under stress.
Perhaps I could use a section of a different material for the grade section.
-Kevin
My subroadbed is good old (used-to-be) cheap 1/2" plywood. It bends easily into a grade. My risers average around 15-16" on center, but that varies like mad. It more dependent on joist spacing, which itself depends on the overall benchwork geometry..
Mark P.
Website: http://www.thecbandqinwyoming.comVideos: https://www.youtube.com/user/mabrunton
PruittIf you're using a plywood subroadbed in a cookie-cutter approach, the plywood will form a natural vertical curve without a hump between the last flat riser and the first one in the grade as you begin downwards.
I wonder where the happy medium is.
Living the dream.
You want a vertical curve (a gentle one) at the top and the bottom of a grade to ease the transition between the grade and the flat. But as I understand what the OP is saying, the track from the grade extends upwards beyond the desired level at the top, then curves back down to the level track, forming the "hump." You don't want that.
If you're using a plywood subroadbed in a cookie-cutter approach, the plywood will form a natural vertical curve without a hump between the last flat riser and the first one in the grade as you begin downwards. DON'T put a splice in the grade transition area if you can possibly avoid it.
Foam will form a natural curve in the same way as the plywood, but if it's too abrupt the foam may break after a time. You certainly don't want that.
York1 Doughless (Reminds me of my home town where they had an old UP/BN grade crossing. Once BN started running 125 car Wyoming Powder River coal trains every two hours or so, they could not wait at the crossing for UP to give permission. With some mischievious delays no doubt. So they began piling up dirt onto perfectly flat prairie to build a flyover overpass. I think the first dirt pile-up "riser" had to start about 5 miles away from the crossing to lift the track at a smooth grade. BNSF coal train crossing over UP coal train at Douglas's home town. These tracks used to be a noisy set of tracks crossing tracks. This is a long section of elevated track, crossing many city roads and highways in addition to UP's tracks. A friend who worked for BNSF said the railroad regretted making the crossing a single track. It's double track on both sides of this elevated section:
Doughless (Reminds me of my home town where they had an old UP/BN grade crossing. Once BN started running 125 car Wyoming Powder River coal trains every two hours or so, they could not wait at the crossing for UP to give permission. With some mischievious delays no doubt. So they began piling up dirt onto perfectly flat prairie to build a flyover overpass. I think the first dirt pile-up "riser" had to start about 5 miles away from the crossing to lift the track at a smooth grade.
BNSF coal train crossing over UP coal train at Douglas's home town. These tracks used to be a noisy set of tracks crossing tracks. This is a long section of elevated track, crossing many city roads and highways in addition to UP's tracks.
A friend who worked for BNSF said the railroad regretted making the crossing a single track. It's double track on both sides of this elevated section:
Ah yes, those UP trains. Very busy double mainline, and I think a small yard that about a dozen city streets cross. 7 or 8 tracks IIRC.
In those days, sitting at one of the crossings waiting for a 100 car train to cross, getting ready to hit the gas pedal, only to have the crossing gates lift half way before the bell sounded again and dropped the gates for another 100 car train heading in the other direction. Groan.
You can see the headlights of another big loco facing the camera.
Doughless(Reminds me of my home town where they had an old UP/BN grade crossing. Once BN started running 125 car Wyoming Powder River coal trains every two hours or so, they could not wait at the crossing for UP to give permission. With some mischievious delays no doubt. So they began piling up dirt onto perfectly flat prairie to build a flyover overpass. I think the first dirt pile-up "riser" had to start about 5 miles away from the crossing to lift the track at a smooth grade.
York1 John
Doughless richhotrain On my old layout, I cut all of the 2x4 legs exactly 36". But, I failed to take the unevenness of the basement floor into account. Turned out, I had tons of unintended uncouplings where the uneven layout surface produced a hump. I could not entirely eliminate the hump but I did succeed in a gradual rise in the track over a length of 8 feet or so to level out the hump as much as I could. If you can do what Brent did, that will eliminate the hump.
richhotrain On my old layout, I cut all of the 2x4 legs exactly 36". But, I failed to take the unevenness of the basement floor into account. Turned out, I had tons of unintended uncouplings where the uneven layout surface produced a hump. I could not entirely eliminate the hump but I did succeed in a gradual rise in the track over a length of 8 feet or so to level out the hump as much as I could.
On my old layout, I cut all of the 2x4 legs exactly 36". But, I failed to take the unevenness of the basement floor into account. Turned out, I had tons of unintended uncouplings where the uneven layout surface produced a hump. I could not entirely eliminate the hump but I did succeed in a gradual rise in the track over a length of 8 feet or so to level out the hump as much as I could.
If you can do what Brent did, that will eliminate the hump.
richhotrain Doughless The hump is unavoidable Great point, Douglas. When I first read the OP's question, that was my thought, but I was anxious to see if others thought that the hump might be avoidable. Doughless but you want it to be gradual, so you have to alter the supports to smooth it out. Probably several, including along the flat run of track to ease the downward angle. On my old layout, I cut all of the 2x4 legs exactly 36". But, I failed to take the unevenness of the basement floor into account. Turned out, I had tons of unintended uncouplings where the uneven layout surface produced a hump. I could not entirely eliminate the hump but I did succeed in a gradual rise in the track over a length of 8 feet or so to level out the hump as much as I could. Rich
Doughless The hump is unavoidable
The hump is unavoidable
Great point, Douglas. When I first read the OP's question, that was my thought, but I was anxious to see if others thought that the hump might be avoidable.
Doughless but you want it to be gradual, so you have to alter the supports to smooth it out. Probably several, including along the flat run of track to ease the downward angle.
(Reminds me of my home town where they had an old UP/BN grade crossing. Once BN started running 125 car Wyoming Powder River coal trains every two hours or so, they could not wait at the crossing for UP to give permission. With some mischievious delays no doubt. So they began piling up dirt onto perfectly flat prairie to build a flyover overpass. I think the first dirt pile-up "riser" had to start about 5 miles away from the crossing to lift the track at a smooth grade. Maybe farther.)
I think experienced carpenters install those little screw in adjustable metal pads at the bottom of each leg to account for the uneven concrete.
TrainsRMe1 I notice I have a vertical curve ( A hump in the track at the crest of the hill), how can I fix this problem???? Thank You and take care.
So, I have only built one layout that had grade transitions of any kind. That was my third N scale layout. It did not get very operational before I switched to HO scale, but I had no problems with grade transitions.
I think that was just luck, because I know I did not do anything special while building it.
My next layout will need to have a 5% grade to get to an over/under spot. I have built a mock-up of the grade and tested it. I have found I need to limit this section to 50 foot freight cars max, and my Walthers Trainline FA can pull four cars up the grade and a caboose with no issue. My Walthers Proto FM switcher can manage three cars and a caboose.
My experiments had no problems with vertical transition, and it was made of cardboard.
There was a noticeable hump at the top, but I figured with 5% grade this would not be something that could be avoided.
On my friend Randy's NORFOLK SOUTHERN N scale layout there is a helix inside a mountain. The grade starts right at the tunnel portal, on straight track, and is a gradual transition to the 2.5% grade of the helix.
I think the transition takes place over about 18" of straight track, and this is also where the track changes from Atlas to Kato for the hidden helix.
There have been no issues with the helix that I know of.
Doughlessbut you want it to be gradual, so you have to alter the supports to smooth it out. Probably several, including along the flat run of track to ease the downward angle.
If your climb between levels is long enough spline may be something to consider. There is no measurable transition point at either end of my up and down. Both the horizontal and vertical flow is perfect requiring no corrective measures.
This was the first layout I built using spline and I am sold on it over cookie-cutter. I found building the spline a whole lot of fun that was over too soon. It was really cheap to build as well. One sheet of hardboard was about $8.00 and that buys you a whole lot of roadbed.
Here is the spline with foam installed around it.
You didn't say what material you are using, but I agree a rasp is a great tool to smooth things out. Also, caulk, spackle, tape, or a long list of other stuff is good for filling dips and holes. I use caulk as a leveler as it finds level just like water does before it dries. The roadbed should be as perfect as you can get it, the time you take to do this is worth it every time.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
The hump is unavoidable, but you want it to be gradual, so you have to alter the supports to smooth it out. Probably several, including along the flat run of track to ease the downward angle.
What you want to build is called a "vertical easement". It eases the transition from angle to flat. You don't want that transition to be abrupt, as you noted.
A picture might be useful. I minimized the transition issues by placing the joints between vertical supports (not on them), and by adding fairly long supports under the joints, solidly fastened by drywall screws. Any humps, if any, can be sanded away. But I find that uneven track is almost impossible to avoid. Shims can be added under the roadbed. I used various types of coffee stirers (cut in size) to achieve this. Once the roadbed and track was in place, I had to add extra styrene shims here and there (expecially on the curves) to ensure that the elevations were smooth, and that the track is level laterally. My 22'' curves are level to the point where I can run 10 driver brass engines without derailments...