01-03-2009, 01:42 PM
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TRACK PROBLEMS
I think track can be catagorized as straight, curved, switches, or crossovers.
I am going to link some web pages from the NMRA. The first page is a page from the NMRA store, and I'm linking the nonmembers page. All of the items in the NMRA store have both members prices and nonmember prices, the non member pages show nonmember prices. You can go to the NMRA site and navigate to the member store pages to get the member prices if you are a member, but this information is intended for nonmembers as well as members to find.
The first tool I would recommend for anyone building a layout is this one
<!-- m --><a class="postlink" href="https://www.nmrastores.com/cgi/NMRA_...TION=NEXT+PAGE">https://www.nmrastores.com/cgi/NMRA_...TION=NEXT+PAGE</a><!-- m -->
The NMRA gauge can test track gauge, flangeways & frog clearance, tunnel portal clearance, loading dock and station platform clearance, wheel gauge, and coupler height. There may be some other things it tests as well that I'm forgetting. It is as close to a universal measuring tool as I've seen. It is the essential tool to test just about everything that has anything to do with track. You can get them at hobby shops for the nonmember price or maybe a dollar more, but to me it is an essential tool for anyone building a model railroad layout. They offer them in sizes from n scale to O scale (not Lionel O gauge). If you model Nn3 or Z, Lionel, Marx, or LGB I don't know of anything for you to use. Modelers in those scales may help out with suggestions here. Get one in the appropriate scale for the layout you are building.
Things to look for in trackwork:
1: Make sure all of it is in gauge. I can only think of 2 causes for commercial track to be out of gauge. You could get a piece of defective track (I've never heard of this problem). I think it is a very rare situation. If you buy used track at a swap meet or on E bay, you might get damaged track. The other and I think most common problems for commercial track being out of gauge is improper installation or assembly of track. All of the commercial track except the old "True Track" (out of production for many years) use plastic tie strips. There was some track manufactured in the 1960's that used a paper/fibe tie strip with staples to hold the rails to the ties. You don't want to use any of that stuff. The only thing it is any good for is as a source for bare code 100 rail in ho scale. I don't know if it was offered in any other scale. The most common way to knock commercial track out of gauge is to use track nails to mount your track to your roadbed and then drive the nails in too tight! If you use track nails to mount roadbed, make sure you leave a little clearance between the bottom of the nail head and the top of the tie. You could make a "feeler gauge" out of a business card, and make sure when you put in your nails you have clearance to slip the business card under the nail head and above the ties. What tends to happen is the nail is driven in too deep and the tie bends pulling the rails together.
2: Do transitions for every curve both horizontal and vertical. What is a vertical curve? When you go from a flat level run of track ans start up a hill, or have been climbing a grade and level out on top before going down again, you have encountered a vertical curve. If you have a "whoop de do" in your benchwork or roadbed surface that causes a dip or bump in the track, you have a vertical curve. Sometimes you might have a spot on your track where 4 axle diesels and rolling stock goes through fine, but 6 axles diesels, passenger cars, and steam engines seem to derail from time to time, even on a straight section. Look closely while running the equipment that has a problem very slowly across the problem area and see if the front or rear wheel set of one or more trucks tends to lift off the rail. A bump or dip in the rails on a straight section may derail long wheelbase trucks sometimes, a bump or dip in a curve will do it just about everytime. If you use cork or even some of the new rubber roadbed, make yourself a long sanding block. Get a 1x2 8 inches long and sand it smooth to eliminate any slivers. Now cut a piece of 100 grit sand paper to just fill the 2 inch wide side (you will need a 1x3 for O scale) and glue the strip of sand paper to the sanding block you just made. Now before you lay any track on the freshly installed roadbed, run you sanding block over it to get any bumps out of the roadbed and to bring high spots down to eliminate dips. Also make sure switches are always installed on level "ground." Switches will always cause problems if the base under them is uneven. If you are going to have a switch taking a siding off the high ballasted mainline onto dirt for an industry, keep the entire switch up on the ballasted "high line;" and then let the siding transition to dirt after it comes away from the switch.
To transition from level track to a grade or a grade to level track, I would recommend using plywood subroadbed correctly. I think the new foam grade making stuff from Woodland Scenics probably has grade transitions manufactured in, but I've never had any experience with the product so I can't comment on it either way. When you use a plywood base under your roadbed, DON'T EVER start your grade transition at the point where 2 pieces of plywood butt together! If you do that I can just about guarantee you that you will get a vertical curve without any transition. You may not have derailing issues if the problem is not on a curved piece of track, but you will probably get mysterious uncoupling of your train from the first locomotive that crosses through that vertical curve. The dynamics of what is happening is the locomotive tips up as it starts it's climb, and the rear knuckle coupler drops down and slips out of the coupler behind it. Secure your plywood subbase a few inches before the grade is to start, and bend the plywood into the grade. If the grade is not too extreme, the plywood will form a natural transition into the vertical curve at the start of the grade. In the same way, when you top out at the top of the hill make sure your transition is in the plywood and not where the 2 pieces join. What happens when the train goes "over the top" at a poorly transitioned grade is just opposite of what happens at the bottom, but the results are almost the same. In this case the rear coupler of the engine or a long car swings up outt of the grasp of the knuckle on the car behind. I said the result is almost the same. If you uncouple at the bottom of the grade, the part of the train that uncoupled stays at the bottom of the grade while the rest of the train climbs the hill. If you have an unwanted uncoupling problem at the top of the grade, the uncoupled cars will run uncontrollably at fairly high speed back down the hill, and may get up enough speed to fly right off the track!
For transitions from straight to curved track in a horizontal plain, you must use flex track. Layouts built with sectional track will not have transitions, and they will work, but some long equipment that might make it through a tight radius with transitions may derail when trying to go through the same tight radius without transitions. One trick that might work if your layout is made up of 18 inch minimum radius curves, is to use a section of 22 inch radius at the beginning and end of each curve. If you are already using a 22 inch minimum radius, I don't know of any commercial sectional track bigger than 22 inch radius. This thread was copy pasted from the old site. Since I originally wrote this, manufacturers have come out with 24 and perhaps 26 inch radius sectional track in ho because of the extra length of the modern super power diesels. There have been many methods discussed on how to make transitions by bending yard sticks or bending flex track, or bending what ever. There are also mathematical formulas to tell you how to compute a spiral transition into a curve, but I can't remember those either. A method I was shown that is easy and works great for me is to start and end the first 3 inches or the last 3 inches every curve with the track offset about 1/2 the width of the track outside of the nominal curve radius. In effect the true centerline of the curve will seem to line up on the inside rail of the straight track leading into the curve.
By the way, all commercial turnouts are made with a transition curve built in to any diverging route. In the case of a wye turnout, both routes will have transitions built in from the manufacturer, and the same thing is true for any commercial curved turnout.
2: Do "S" curves correctly. I deliberately did not say to avoid "S" curves. I think a train snaking through a correctly done "S" curve is a beautiful sight! The problem created by S curves has to do with the dynamics of rolling stock being pulled and pulling on the ends. If you locomotive has just come out of a right turn and is going into a left turn, the locomotive will be pulling the car following to the left; but the rest of the train will be pulling that same car to the right. The car will want to take a short cut and cut the corner, but there are no tracks there. The result is a derail or cars laying over on their sides. The solution is to put a straight section in the middle between the right and left turn so the train goes right, straight, then left. The length of the straight section should be equal to the longest car that is going to go through the S curve. There is one exception to this rule. If you are modeling a shortline or branchline that is served by a peddler frieght with one passenger car or combine running at the end of the train instead of a caboose, you can make the straight in the S curve long enough for the longest freight cars that will regularly use the trackwork. Because there is nothing behind the longer passenger car or combine to pull on the back of it, it shouldn't have any problem with the S curve although you will have operate at restricted speeds. Then again, peddler freights operate at low speeds anyway, and most branch lines or short lines running a peddler freight will not have the best trackwork in the country anyway.
Something else that has come to my attention since posting this thread originally is that the guard rails on Atlas turnouts are too far from the rails they are protecting. The stock Atlas switch will allow wheels to fall off the rails and land on the ties between the rail and the guard rail. The fix is simple. Just cut a piece of .015" styrene to the same height as the guard rail and glue it between the guard rail and the main rail. Do it to all guard rails on Atlas switches and then paint the "shim" to match the guard rails.
TRACK PROBLEMS
I think track can be catagorized as straight, curved, switches, or crossovers.
I am going to link some web pages from the NMRA. The first page is a page from the NMRA store, and I'm linking the nonmembers page. All of the items in the NMRA store have both members prices and nonmember prices, the non member pages show nonmember prices. You can go to the NMRA site and navigate to the member store pages to get the member prices if you are a member, but this information is intended for nonmembers as well as members to find.
The first tool I would recommend for anyone building a layout is this one
<!-- m --><a class="postlink" href="https://www.nmrastores.com/cgi/NMRA_...TION=NEXT+PAGE">https://www.nmrastores.com/cgi/NMRA_...TION=NEXT+PAGE</a><!-- m -->
The NMRA gauge can test track gauge, flangeways & frog clearance, tunnel portal clearance, loading dock and station platform clearance, wheel gauge, and coupler height. There may be some other things it tests as well that I'm forgetting. It is as close to a universal measuring tool as I've seen. It is the essential tool to test just about everything that has anything to do with track. You can get them at hobby shops for the nonmember price or maybe a dollar more, but to me it is an essential tool for anyone building a model railroad layout. They offer them in sizes from n scale to O scale (not Lionel O gauge). If you model Nn3 or Z, Lionel, Marx, or LGB I don't know of anything for you to use. Modelers in those scales may help out with suggestions here. Get one in the appropriate scale for the layout you are building.
Things to look for in trackwork:
1: Make sure all of it is in gauge. I can only think of 2 causes for commercial track to be out of gauge. You could get a piece of defective track (I've never heard of this problem). I think it is a very rare situation. If you buy used track at a swap meet or on E bay, you might get damaged track. The other and I think most common problems for commercial track being out of gauge is improper installation or assembly of track. All of the commercial track except the old "True Track" (out of production for many years) use plastic tie strips. There was some track manufactured in the 1960's that used a paper/fibe tie strip with staples to hold the rails to the ties. You don't want to use any of that stuff. The only thing it is any good for is as a source for bare code 100 rail in ho scale. I don't know if it was offered in any other scale. The most common way to knock commercial track out of gauge is to use track nails to mount your track to your roadbed and then drive the nails in too tight! If you use track nails to mount roadbed, make sure you leave a little clearance between the bottom of the nail head and the top of the tie. You could make a "feeler gauge" out of a business card, and make sure when you put in your nails you have clearance to slip the business card under the nail head and above the ties. What tends to happen is the nail is driven in too deep and the tie bends pulling the rails together.
2: Do transitions for every curve both horizontal and vertical. What is a vertical curve? When you go from a flat level run of track ans start up a hill, or have been climbing a grade and level out on top before going down again, you have encountered a vertical curve. If you have a "whoop de do" in your benchwork or roadbed surface that causes a dip or bump in the track, you have a vertical curve. Sometimes you might have a spot on your track where 4 axle diesels and rolling stock goes through fine, but 6 axles diesels, passenger cars, and steam engines seem to derail from time to time, even on a straight section. Look closely while running the equipment that has a problem very slowly across the problem area and see if the front or rear wheel set of one or more trucks tends to lift off the rail. A bump or dip in the rails on a straight section may derail long wheelbase trucks sometimes, a bump or dip in a curve will do it just about everytime. If you use cork or even some of the new rubber roadbed, make yourself a long sanding block. Get a 1x2 8 inches long and sand it smooth to eliminate any slivers. Now cut a piece of 100 grit sand paper to just fill the 2 inch wide side (you will need a 1x3 for O scale) and glue the strip of sand paper to the sanding block you just made. Now before you lay any track on the freshly installed roadbed, run you sanding block over it to get any bumps out of the roadbed and to bring high spots down to eliminate dips. Also make sure switches are always installed on level "ground." Switches will always cause problems if the base under them is uneven. If you are going to have a switch taking a siding off the high ballasted mainline onto dirt for an industry, keep the entire switch up on the ballasted "high line;" and then let the siding transition to dirt after it comes away from the switch.
To transition from level track to a grade or a grade to level track, I would recommend using plywood subroadbed correctly. I think the new foam grade making stuff from Woodland Scenics probably has grade transitions manufactured in, but I've never had any experience with the product so I can't comment on it either way. When you use a plywood base under your roadbed, DON'T EVER start your grade transition at the point where 2 pieces of plywood butt together! If you do that I can just about guarantee you that you will get a vertical curve without any transition. You may not have derailing issues if the problem is not on a curved piece of track, but you will probably get mysterious uncoupling of your train from the first locomotive that crosses through that vertical curve. The dynamics of what is happening is the locomotive tips up as it starts it's climb, and the rear knuckle coupler drops down and slips out of the coupler behind it. Secure your plywood subbase a few inches before the grade is to start, and bend the plywood into the grade. If the grade is not too extreme, the plywood will form a natural transition into the vertical curve at the start of the grade. In the same way, when you top out at the top of the hill make sure your transition is in the plywood and not where the 2 pieces join. What happens when the train goes "over the top" at a poorly transitioned grade is just opposite of what happens at the bottom, but the results are almost the same. In this case the rear coupler of the engine or a long car swings up outt of the grasp of the knuckle on the car behind. I said the result is almost the same. If you uncouple at the bottom of the grade, the part of the train that uncoupled stays at the bottom of the grade while the rest of the train climbs the hill. If you have an unwanted uncoupling problem at the top of the grade, the uncoupled cars will run uncontrollably at fairly high speed back down the hill, and may get up enough speed to fly right off the track!
For transitions from straight to curved track in a horizontal plain, you must use flex track. Layouts built with sectional track will not have transitions, and they will work, but some long equipment that might make it through a tight radius with transitions may derail when trying to go through the same tight radius without transitions. One trick that might work if your layout is made up of 18 inch minimum radius curves, is to use a section of 22 inch radius at the beginning and end of each curve. If you are already using a 22 inch minimum radius, I don't know of any commercial sectional track bigger than 22 inch radius. This thread was copy pasted from the old site. Since I originally wrote this, manufacturers have come out with 24 and perhaps 26 inch radius sectional track in ho because of the extra length of the modern super power diesels. There have been many methods discussed on how to make transitions by bending yard sticks or bending flex track, or bending what ever. There are also mathematical formulas to tell you how to compute a spiral transition into a curve, but I can't remember those either. A method I was shown that is easy and works great for me is to start and end the first 3 inches or the last 3 inches every curve with the track offset about 1/2 the width of the track outside of the nominal curve radius. In effect the true centerline of the curve will seem to line up on the inside rail of the straight track leading into the curve.
By the way, all commercial turnouts are made with a transition curve built in to any diverging route. In the case of a wye turnout, both routes will have transitions built in from the manufacturer, and the same thing is true for any commercial curved turnout.
2: Do "S" curves correctly. I deliberately did not say to avoid "S" curves. I think a train snaking through a correctly done "S" curve is a beautiful sight! The problem created by S curves has to do with the dynamics of rolling stock being pulled and pulling on the ends. If you locomotive has just come out of a right turn and is going into a left turn, the locomotive will be pulling the car following to the left; but the rest of the train will be pulling that same car to the right. The car will want to take a short cut and cut the corner, but there are no tracks there. The result is a derail or cars laying over on their sides. The solution is to put a straight section in the middle between the right and left turn so the train goes right, straight, then left. The length of the straight section should be equal to the longest car that is going to go through the S curve. There is one exception to this rule. If you are modeling a shortline or branchline that is served by a peddler frieght with one passenger car or combine running at the end of the train instead of a caboose, you can make the straight in the S curve long enough for the longest freight cars that will regularly use the trackwork. Because there is nothing behind the longer passenger car or combine to pull on the back of it, it shouldn't have any problem with the S curve although you will have operate at restricted speeds. Then again, peddler freights operate at low speeds anyway, and most branch lines or short lines running a peddler freight will not have the best trackwork in the country anyway.
Something else that has come to my attention since posting this thread originally is that the guard rails on Atlas turnouts are too far from the rails they are protecting. The stock Atlas switch will allow wheels to fall off the rails and land on the ties between the rail and the guard rail. The fix is simple. Just cut a piece of .015" styrene to the same height as the guard rail and glue it between the guard rail and the main rail. Do it to all guard rails on Atlas switches and then paint the "shim" to match the guard rails.