Blue Comet Tender Stringlining?

I'd agree with your analysis, weight always seems to help in this kind of situation.  I suspect the geometry of the smaller tender may exacerbate the problem.

If there is room in the tender that might be an easy fix.  I know my dad had to add lead to some of his tenders in the past for similar reasons.

Steve

String-lining is prevalent operating in a curve when:

• The tender is lightweight plastic, so the down force due to mass is less than if the tender was made of a heavier metal;
• The cars in tow are heavy, and or their rolling resistances are high;
• The cars have a significant overhang because the track radius is small, and or there are too many cars in the train. These situations apply a sideways force on the tender.

Not only do the above cause string-lining, but operation through switches is degraded as well because of the sideways forces on the drivers and trucks.

You could try fitting a few of the self-adhesive weights used for wheel balancing into the interior of the tender if space permits. They are available in various weights, and would be simple to fix and remove as necessary. 

Its because the moose call whistle weighs less than the right one

I have a large box of the 1oz wheel weights that I use to weight cars.  I try to put them as low as possible on the car, for boxcars I put them under the floor or inside on the floor.

Lee,

According to NMRA RP20.1 'O' cars should weigh 5oz + 1oz for each inch of car length.

The RP's aimed at 2-rail scale folks, but it's not a bad starting point for 3-railers.

If the weight is okay, I'd suspect it's a car length/curve size/weight being pulled physics/geometry issue. Adding additional weight beyond the RP might keep the tender on the track, but will create other issues due to increased axle and truck bearing friction.

Interesting - my MTH SG "Tinplate Traditions" Blue Comet 400E tender is EXTRA heavy (weights added) for the same reason!

Other MTH "Tinplate Tradition" 400E's do not have the added weights.

Len, does that formula apply to tenders, too?  Most of the tenders on recent Lionel locos I have bought seem much heavier than that.  I figured tenders were deliberately made heavy so they had that weight to pull well and not stringline.

I only take the NMRA guidelines as just that, a loose guideline.  I'm with Lee, I like the tenders to be extra heavy to add stability.

I have had no such problems.  I have the 2001 version (831 and die cast tender) and pull an entire six car train, minus the seventh sound car, which I don't have, through curves w/minimum of O-72, and a myriad of Ross switches , as well as when so directed, up a 2%grade which curves to the right, midway through a 27 foot run.  Tracking or pulling power around and through the layout is not a problem. The loco doesn't have to work that hard. Is it possible that the wheel gauging on the tender is just a tad off and thus the cause of the problem?  Just a thought.

Is the switch perfectly level, and installed correctly, so as to avoid any unintentional superelevation?

Lee,

The RP is intended for all cars, including tenders, but like I said - the Recommended Practices are mainly aimed at 2-railers, and as 'Gunrunner' said RP's are guides, not standards.

If your tender already meets the RP guidelines, and adding the weight of the page holder 'cures' the problem, I'd weigh the page holder and see if adding that much weight to the tender gets you rolling. You want to keep the added weight as low as possible on, or under, the frame. Tom has A-Line stick on weights in stock if you need any.

I should be in my shop all week, including Monday this week, if you want to stop by with the tender.