Traction Tires

[rbryce1]

I have a Riverossi 4-6-4 Hudson which has traction tires and it pulls like the devil up 3% slopes.  I have Bachmann 2-8-8-4 EM-1 engine that is either straining or slipping when pulling the same freight at the same speed up a 3% slope.  The EM-1 will absolutely pull the freight up the grade with some more throttle, but it slows without doing this while the Riverossi does not.  I have not looked real close to see if the EM-1 has traction tires, but I do not think it does.

I have the ability to put traction tires on the EM-1 with Bull Frog Snot, but my question is:

Are engines designed to slip at a certain load point to protect the motor from overload, or do they just slip due to low weight or poor traction.  I really think that adding traction tires to the EM-1 will enhance it's pulling ability, but don't want to overload it at the same time.

[jonathan]

Previous discussions of "BFS vs. Traction Tires" leads to some interesting opinions and experience.

I have added BFS to one drive wheel on my older models, mostly as an experiment.  I have doubled the pulling capacity of those old locos using this stuff.

On newer models, like your EM-1, I prefer to add weight, perhaps an ounce, maybe two.  I have no expertise in this, but the added weight does increase pulling power, and still allows the wheels to 'slip' if the locomotive is overloaded.

A word of caution:  The EM-1 has more moving parts in order to drive two 8-wheeled trucks.  More things can go wrong by overloading the drive train.  My humble opinion is to not add traction or weight to this locomotive, to ensure it runs for a very long time.  This locomotive is mechanically complicated.

Some folks really like traction tires.  I feel like it's one more part that will need to be replaced over time.  I'd rather pull fewer cars, or better yet, get two EM-1s, and double head 'em.  My rule is to restrict the EM-1 to no more than a 20-car train, with gentle grades.  3% is a bit too steep with long trains.

Regards,

Jonathan

[jward]

as a general rule, i avoid locomotives with traction tires like the plague.  most that come with them are poor quality train set locomotives from years gone by. traction tires also cut down on the number of wheels which pick up electricity from the track. they also cause the wheels to be out of round. in my experience, a locomotive with traction tires (diesel) will bounce itself off the track once the wheels slip.

the best solution for pulling grades is to either cut down train length, or double head the locomotives.

i thought the only 3% grade you had was coming up from your turntable, and only used by light engines?

[sd24b]

I have a Riverossi 4-6-4 Hudson which has traction tires and it pulls like the devil up 3% slopes.  I have Bachmann 2-8-8-4 EM-1 engine that is either straining or slipping when pulling the same freight at the same speed up a 3% slope.  The EM-1 will absolutely pull the freight up the grade with some more throttle, but it slows without doing this while the Riverossi does not.  I have not looked real close to see if the EM-1 has traction tires, but I do not think it does.

I have the ability to put traction tires on the EM-1 with Bull Frog Snot, but my question is:

Are engines designed to slip at a certain load point to protect the motor from overload, or do they just slip due to low weight or poor traction.  I really think that adding traction tires to the EM-1 will enhance it's pulling ability, but don't want to overload it at the same time.

drivers slipping is the safety valve for saving your motors.  I can't speak for steam but I have used BFS on several diesels where I couldn't add weight.  I too prefer the weight vs. traction tires.  BFS did increase the TE.  My next test will be on a Bachmann SF Northern.   Phil

[ebtnut]

The real test as to motor safety is to check the amp draw of the motor.  In ancient, open frame motor times the usual rating for something like a DC-70 motor was 1 amp.  If your model began slipping as it reached that rating, it was OK.  The rating for today's high efficiency motors is much less than 1 amp, and in most cases the data sheets that come with the models don't give that info.  I wouldn't be overly agressive in adding weight to today's models.  In the case of the EM-1, some additional weight would likely help, but it should be distributed evenly so that both engines get some of the weight.  How and where to add the weight will depend on what space is available within the boiler or maybe between th frames. 

[rbryce1]

I thought the only 3% grade you had was coming up from your turntable, and only used by light engines?

Jeff,

You have a pretty good memory!!  My permanent layout will only have a max 3% grade for just engines, but that one is still on the drawing boards.  This one is our smaller (4'-6" x 12') double dog-leg (sort of like a long "W" without the middle "V") Christmas layout which is under construction right now.  

It has 3 tracks (none of which are interconnected) with 3 trestles to cross over a stream leading to a pond.  There is a seashore with a light house to the right, a residential district in the center and a recreational park with a pond and a car show on the left.  The scenery on the left is Autumn scenery and it gradually turns to Winter in the middle and on the right for the Christmas scenery.  All the tracks on the rear wall are elevated, one is 2" overall rise, the middle is 1.5" and the inner is 1" in total rise.  The outer rail will have the Alaska McKinley Explorer running on it, the center will have a freight train with the 4-6-4 Hudson and the center or residential rail section will have the Bachmann "San Fransisco Cable Car" is recently successfully installed a decoder in for DCC operation.

The permanent layout will be constructed in the room where we are currently building the smaller portable Christmas layout, which will be moved to the living room next month.  After Christmas, it will be disassembled and stored till the next year.  It is constructed totally on a large sheet of 3" composite aluminum-foam wall panel, like the kind used for the walls and roof on Sunrooms.  Tons of strength (you can walk on it) and light as a feather (I can carry it myself, but far to bulky for just one person).

At any rate, I just bought the EM-1 at the train show a few weeks ago and tried to see how well it compared with the other engines on the Christmas layout, and that was what I had found.

Actually, on the permanent layout, the EM-1 will be pulling about 9-10 freight cars and only be on the Mountain rail section, of which the max slope is a 2.0 slope with 28" R turns and a total of a 3" rise.  The second train on that rail will be the Alaska McKinley Explorer with 5 McKinley cars and 2-3 Alaska diesels.  This way I can fit an entire train on a siding loop.  The EM-1 will not see the turn table, as it is far too long to fit on it anyway.

[rogertra]

I agree with jward and Johnathon and others.

Either add weight or double head or reduce the length of the train(s).  However, do not add so much weight that your wheels will not slip under full load.  Spinning wheels are a safety valve.

I can't speak for BFS but it's probably the same a traction tires.  Wheel spin will save your motor, see above.   Traction tires and probably BFS do not let the wheels spin and you can burn out a motor. Very expensive, just for the sake of a few extra cars.

For me, no traction tires and, until I experiment, no BFS.  I'd rather add weight, especially to my steam, which I do as a matter of course anyway, or double head, which is more prototypical or reduce train length(s), again, prototypical.  You could even prototypically double the hill.

Of course, the obvious solution when designing the model railroad is not to have grades over 2% in the first place.

[Doneldon]

I have the ability to put traction tires on the EM-1 with Bull Frog Snot, but my question is:

rb-

You don't use BFS to add traction tires. It's a coating for (usually) one set of drivers. Actual traction tires are rather like a rubber band which is a little smaller than the circumference of your wheel. The "tire" rests in a groove in the metal wheel.

Allow me to second the advice about being careful with BFS and traction tires. You can burn out a motor or a PCB if your wheels can't spin.

                                                                                                                                -- D

[rbryce1]

I was not going to put the BFS on the traction tires!  The EM-1 does not come with traction tires.  

I am aware of what a real traction tire is and why they are there, as my Riverossi 4-6-4 Hudson has them.  I also see what the 4-6-4 does without them.  BFS is an alternate to using the actual tire should yours begin to fall off like mine did on my Riverossi and you can't find a replacement.  I found and purchased the BFS in the event I needed to use it as a replacement for the correct traction tire, then a day or so later found and bought the correct traction tire.  Still have not bought the tool I need to install the actual traction tires on the Riverossi and I don't feel like using pliers and screwing up the head of the microscopic bolts on the engine wheels.  

My main concern is whether adding the BFS to the EM-1 may overload the EM-1 by having the wheels grip rather than spin at the point where the wheels spinning are protecting the motor from overload, or if the wheels are simply spinning.  Kind of like having a race car that has enough power to spin the rear wheels and it's drive train can handle it, so you go to larger tires which allow you to use the power you were losing by the wheels spinning.  At some point, you reach the condition where the tires are so large they no longer spin at all under any condition, and if you continue to push it, the gears now break.  Don't know if the EM-1 is already designed at that point or it can take more traction without problems.

Kind of like to hear from the Bachmann on this as well.

[MAGER]

Do DCC decoders have current limiters for protecting the motor? If so, that should protect the motor.

[rbryce1]

Do DCC decoders have current limiters for protecting the motor? If so, that should protect the motor.

Actually, and I'm sure I'm going to be corrected if I am wrong, I think it goes the opposite way.  You need to buy a decoder with a higher rating than the stall speed current of your engines motor.

If you apply full power to your engine while holding in in place with just enough pressure to stop the wheels from turning, and read the current being drawn at that time, that is the stall speed current draw.  You need a decoder with a higher current rating than the stall speed current or you may burn up the decoded.

Don't think there is any protection the other way.

[Bucksco]

Sounds to Bachmann like you are pushing it up too steep a grade.....

[richg]

Do DCC decoders have current limiters for protecting the motor? If so, that should protect the motor.

Actually, and I'm sure I'm going to be corrected if I am wrong, I think it goes the opposite way.  You need to buy a decoder with a higher rating than the stall speed current of your engines motor.

If you apply full power to your engine while holding in in place with just enough pressure to stop the wheels from turning, and read the current being drawn at that time, that is the stall speed current draw.  You need a decoder with a higher current rating than the stall speed current or you may burn up the decoded.

Don't think there is any protection the other way.

Some decoders like the Tsunami have over temp protection, I know the Tsunami do but I would never depend on that. Then the fuse on the decoder opens. Send the decoder back for repair.
Measure the motor current carefully is about the only way to be somewhat safe. A multimeter for DC and a DCC amp meter, RRampMeter, for DCC layouts.

Rich

[rbryce1]

Sounds to Bachmann like you are pushing it up too steep a grade.....

Bachmann,

3% grade.  Again, only the EM-1 is having the problem.  Please review my 1st post in this thread for the specifics.  Is 3% too much for the EM-1?

[Bucksco]

Like I said - too steep...
Also - how clean is the track?