points on a medium incline?
- Thread starter dgrafix
- Start date
It doesn't matter unless there is a change in grade immediately adjacent to the switch. If it's just a switch in a grade, no problem. If either route breaking off from the switch changes grade, it's best to have a car length or two at least between grade change and the switch.
skyliner
Well-Known Member
I'm going to go with "B," it should be fine. I have a switch on a 3% grade (HO, code 83 Walthers #8) and although that's a considerably more gradual turnout than your #5, you should be ok. As mentioned above, watch out for elevation changes or curves close by, but it sounds like you've got that accounted for already. But even in my case, I've got a curve immediately preceding the switch and it still runs smoothly.
One other very minor consideration is that adding the change in direction (i.e. the diverging leg of the switch) on a grade will increase the power required to pull a train up that hill, similar to a curvy uphill climb vs. a straight climb. I've noticed this in my layout in that some heavy trains going up can take the straight leg of the turnout just fine, but will stall on the diverging leg due to that slight additional resistance from the curve.
One other very minor consideration is that adding the change in direction (i.e. the diverging leg of the switch) on a grade will increase the power required to pull a train up that hill, similar to a curvy uphill climb vs. a straight climb. I've noticed this in my layout in that some heavy trains going up can take the straight leg of the turnout just fine, but will stall on the diverging leg due to that slight additional resistance from the curve.
dgrafix
Well-Known Member
Thanks for the reply. My layout will be mainly running HSTs which are mostly center driven and not nearly as long or heavy as a freight train. The max I can realistically run on my layout is 8-10 car sets (around and up to 1.2 meter length at N scale, which is my station and rail yard maximum ... or 192 real meters)I'm going to go with "B," it should be fine. I have a switch on a 3% grade (HO, code 83 Walthers #8) and although that's a considerably more gradual turnout than your #5, you should be ok. As mentioned above, watch out for elevation changes or curves close by, but it sounds like you've got that accounted for already. But even in my case, I've got a curve immediately preceding the switch and it still runs smoothly.
One other very minor consideration is that adding the change in direction (i.e. the diverging leg of the switch) on a grade will increase the power required to pull a train up that hill, similar to a curvy uphill climb vs. a straight climb. I've noticed this in my layout in that some heavy trains going up can take the straight leg of the turnout just fine, but will stall on the diverging leg due to that slight additional resistance from the curve.
Selector
Well-Known Member
This question has also been asked of bridges. The answer, as correctly stated several times, is that it doesn't matter. Ideally, for bridges, the approaches on either end are tangent rails for about a long car length, but not strictly necessary. However, for a turnout, you want the super to match if it's there, and then only if it's on a curve. On our layouts, for whatever reason, we sometimes end up with a slight rail elevation disparity even on tangent rails. If it's there, whether by accident or by design, make sure the turnout sits the same way or you'll have troubles.
The one caveat to turnouts on grades, especially if there is super present, is that the departing/diverging route will also be on a grade. Whether it is down-grade departing or up-grade, make darned good 'n sure your planning takes the geometry of that route beyond the turnout into consideration. You may have trouble with clearances into a planned tunnel or under an overpass, or over a lower track.
Actually, there is one other thing that could trip up the modeler: If the turnout is placed partway along a pre-determined length of vertical easement into, or out of, the grade, take that into account. The turnout can't practically be curved vertically unless you build one by hand with that element included. It CAN BE DONE, but ya gotta know what you're doing, and as with all changes to trackage on our pikes, make them nice 'n gradual. Abrupt changes will cause no ends of grief.
The one caveat to turnouts on grades, especially if there is super present, is that the departing/diverging route will also be on a grade. Whether it is down-grade departing or up-grade, make darned good 'n sure your planning takes the geometry of that route beyond the turnout into consideration. You may have trouble with clearances into a planned tunnel or under an overpass, or over a lower track.
Actually, there is one other thing that could trip up the modeler: If the turnout is placed partway along a pre-determined length of vertical easement into, or out of, the grade, take that into account. The turnout can't practically be curved vertically unless you build one by hand with that element included. It CAN BE DONE, but ya gotta know what you're doing, and as with all changes to trackage on our pikes, make them nice 'n gradual. Abrupt changes will cause no ends of grief.
On the original part of my layout, I violated these rules many times. I have very little flat areas and most of my turnouts are on some type of incline. My suggestion is be be prepared for adjustments. I have lots of shims and it is amazing what a few thousandths can do. My layout is HO scale. After a couple years of tweaking, I am about ready to add ballast but if I was starting over, my layout would not have inclined turnouts.
Just to add some clarification of my post above. I model mid 50’s because I can run both steam and early diesels. The longer the locomotive, the more problems you will encounter. I was very careful about allowing transitional radius on curves before and after turnouts but I did not put as much thought into vertical transitions. A longer locomotive such as the Big Boy is not nearly as forgiving as a gp7. Also, longer freight cars can also be a problem. 40’ cars will work fine but 60’ will sometimes uncouple as the car crests an incline with body mounted couplers. My solution on those are small rubber bands on each coupler. Passenger cars are more forgiving if using Talgo mounted couplers. The Mchenry’s will lock in the closed position which really helps to prevent uncoupling while in motion.
