I believe I've mentioned this on the forum before, but I have a siding on my layout where space restrictions dictated I hand-lay a 21"/17" curved turnout at each end. I did do some testing to make sure my engines would negotiate the tight 17" radius, but now that it's in place on the layout, I realize I didn't check whether my only operable steamer would run through both legs of the turnouts, and of course it doesn't. The problem occurs at the frog (big surprise), and it appears there just isn't enough side play for the lead and trailing drivers to stay on the track while the middle drivers are squeezing through the frog and guard rails.
I have two other steamers that don't run right now, but pushing them through the tight radius leg, my MDC 4-6-0 and Mantua 2-8-2 both seem to clear without binding. I think the 4-6-0 has more side play than my 2-8-0, and the 2-8-2 clears because its middle drivers are blind. So, my thinking is that maybe the 2-8-0 would work if its middle drivers were also blind. In my mind, the effort I would have to go into to redesign the siding, tear up the existing turnout, and re-lay one with larger radii is greater than the effort to re-work the steamer, and if it is not practical to remove the flanges from two of the steamer's drivers, I would rather not run the steamer than rework the turnout.
I'm thinking this could be as simple as applying full power to the motor and holding a file against the flanges to turn them down. Alternately, it might also be possible to remove the two drivers, and somehow rework them on the workbench. Or, if there were replacement drivers available that were a drop in fit, that might be the way to go.
Of course, my question is whether anyone has attempted to remove the flanges from their Spectrum 2-8-0 using any of the listed methods (or a better idea)?
As always, your thoughts and advice will be greatly appreciated.
Tom
A caution to think about. In most cases I know of, blind drivers have significantly wider tires than flanged drivers. On the prototype, this is to prevent the blind driver from falling off the rail head - although I've heard this still happened on more than one occasion on really sharp curves.
In the model case, a narrow tread blind driver that drops even the slightest amount when off the railhead will jam and cause a derailment. Theoretically, a rigid frame locomotive will not allow the driver to drop. But it only takes a few thousandths of an inch drop to create the edge that prevents the driver from getting back on the railhead. If the blind drivers are sprung, they must stay on the railhead. I don't know whether the Bachmann 2-8-0 drivers have any vertical play or not - I don't own one. FWIW, this tread width versus gauge widening on curves is why Proto87 locomotives have larger minimum radii than the coarser wheels of NMRA-spec.
I'm kind of surprised at the issue and proposed cure in the 1st place. Bachmann Spectrum steamers are known for having lots of lateral play (too much IMHO) to allow them to get around much sharper curves than they should. I suspect that an honest 17" radius would not stop a Spectrum 2-8-0 in proper working order. There is something else wrong - the radius is much tighter than 17" at some point or has a horizontal kink, the wheels are out of gauge, lateral motion is not there, track is out of gauge in the turnout, the flangeways and guard rail locations are not to spec, or the turnouts have a "bump up" in them - some or more of these are possibilities that I would check for before removing flanges. I find your comment interesting that the 4-6-0 has more lateral play than the Spectrum 2-8-0 - I suspect a problem here.
my thoughts, your choices
Fred W
I think Fred has hit the nail on the head - I own eight Spectrum 2-8-0's, and while I don't run them on 18" radius, I can not imagine that one would not run on a smooth well laid 17" radius curve.
Sheldon
I'll certainly take the last two comments seriously and take another look at my trackwork. However, by definition, a curved turnout shouldn't have a "smooth" radius to it - it's supposed to be straight throught the frog. I used a Central Valley #7 tie strip with circuit board ties at the important spots, so at least some of the variables have been eliminated.
Thanks for the input so far. I'd still like to hear more ideas on how to resolve my dilemma.
Thanks,
Tom,
Can you get someone to 'loan' you a Spectrum 2-8-0 to see if theirs will negotiate your turnouts? This way you will know if your 2-8-0 is the problem.
Bob
Life is what happens while you are making other plans!
I know I have read some years ago that some who lay hand laid track"widen" the track spacing a little on curves but do not remember how much. Not sure I could find the article but you most probably have manufactured track.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
potlatcher ....However, by definition, a curved turnout shouldn't have a "smooth" radius to it - it's supposed to be straight throught the frog. I used a Central Valley #7 tie strip with circuit board ties at the important spots, so at least some of the variables have been eliminated. Tom
....However, by definition, a curved turnout shouldn't have a "smooth" radius to it - it's supposed to be straight throught the frog. I used a Central Valley #7 tie strip with circuit board ties at the important spots, so at least some of the variables have been eliminated.
I think you have found your problem. Bending a conventional #7 turnout, and expecting it to have a smooth approximation of a 21"/17" radius is rather wishful thinking.
In a curved turnout, the frog # determines the difference between the two radii, and I doubt a #7 frog will get you a full 4" difference in radii at such a small outer radius. Which means your inner curve is considerably sharper than 17" in places to get a 17" radius substitution. And a #7 frog is a fairly long straight piece of rail, which again requires much sharper curves elsewhere in the turnout to achieve a 17" radius substitution.
Curved frogs are quite possible in handlaid turnouts, I make them myself. If you fill the frog with solder and then carefully cut out the flangeways with a flexed hacksaw blade, you don't even have to be that accurate on filing the angles of the frog rails. In the past, I've lapped the frog rails rather than trying to get an even split in the frog angles. By constructing curved frogs, particularly at the smaller radii, a constant radius can be maintained through the turnout. I use 18" constant radius through the inner leg of my turnouts when located on curves. I draw the curves and then bend the rail to follow the drawn lines. FWIW, the British prototypes use curved frogs for smoother operation. US prototypes generally use straight frogs because fewer stocks of spares are needed for pre-made frogs. In the days before pre-made frogs, some US railroads would construct what appear to be curved frogs out of rail on hand.
The next fact of life is that the points need to specially shaped to fit a curved turnout. Otherwise, the track gauge will be too narrow or too wide at places through the points. The inner point, in particular, must curve to follow the outer radius instead of being straight as it comes from the turnout kit. Again, the smaller the radii of the curves in the turnout, the more critical the curves in the points become. The points will often become unequal in length at smaller radii and/or large differences in path radius. Guard rails must also be curved to maintain correct check gauge and flangeway throughout the length of the guard rail.
Before I would do any locomotive modifications, I would carefully check the entirety of the 2 turnouts very thoroughly with an NMRA gauge. Any out-of-tolerance spots need to be corrected. Personally, I would much rather re-lay those turnouts than make significant modifications in the locomotive like removing driver flanges. Until the turnouts are right, there will always be some locomotives/rolling stock that will derail on it. Problems in track are potential derailers for all rolling stock, where fixing a piece of rolling stock to get through questionable track only fixes that piece of rolling stock.
Another option is to rebuild with Walters #6.5 curved turnouts. These are supposedly 24"/20" radius, but have been measured much closer to 24"/18".
I suspect that under its own power, your Mantua Mike is going to struggle with the inner path of those turnouts. It's a whole different dynamic from when being pushed by hand.
The surest way to test is with an NMRA gauge and a variety of locomotives.
potlatcher ... by definition, a curved turnout shouldn't have a "smooth" radius to it - it's supposed to be straight throught the frog.... Tom
... by definition, a curved turnout shouldn't have a "smooth" radius to it - it's supposed to be straight throught the frog....
Tom, I don't understand your statement above. I have several W/S curved turnouts, 7.5's and a single #8, and I fashioned a hand-laid #10. In every case, the radius from points rails through either route is curved. It is just that the inner is that much sharper. The W/S curved turnouts probably don't have a true curved frog, but the hand-laid one is slightly curved.
In the case of my #7.5's, and since verified by several layout builders in a thread about four years ago, their inner route is quite a bit tighter than advertised. I recall the seller reading his charts and telling me that the W/S 7.5 had an inner/diverging route radius of 24", my absolute given for a minimum radius. I found it to be closer to 21", and had to cut through all the webbing between the ties on both routes from the frog on and bend the curves outward. Thankfully, I was able to achieve my minimum that way....but what a nasty surprise and bit of work I had before me.
Crandell