I have seen alot of times car weights on here but never engine weight. For optimum performance lets say a GP 40 what would the scale weight be? I know there must be a scale somewhere out there. If anyone knows let me know.
Recomended wts have nothing to do w/ prototype proportianality, it’s about having enough wt to hold the track. Generally, the wider the curves and the lighter the grade the less wt you need. For most of us about 4 oz. for a 40’ car(I start @ 3.5) plus 1/2 oz for every additional 10 ft. of car length.
For engines it’s all a matter of how much pulling power you want. For most MRRs the wt of the engine out of the box works. If you’ve got serious grades amd/or run REALLY long trains you’ll want as much engine wt as you can get
BLI steamers run in the 16-20 oz range. I would guess that the various manufacturers tend to keep their diesels in that range as well, maybe even a bit heavier.
In 1:1 scale a GP40 would weigh around 263,000 lbs. It could be heavier, if the railroad wanted it to be.
In general terms, you can stuff as much weight in an engine as you can until just before the engine stalls, (wheels stop moving when held in a stationary position).
I usually weight 4 axle units to a max of about 17-18 oz and six axle units 18-22 oz. I do have a couple of TigerValley (white metal) Alco C-628s that weigh in at 34 oz with no added weight! A couple of my bridges actually bend a bit when these monsters cross!).
I do pull long trains (65-90 cars, all weighted). Max grade is 2%.
Before I reply here, I’m no electronics whiz kid, but my concern would not be scale weight. My big concern would be the ampherage the motor can take without damage to it and that the wheel slip amps would not exceed the amp rate of the motor and not over weight the loco to exceed this, other wise you my get smoke where it ain’t wanted!! Ken
This doesn’t make sense to me…maybe it just means that I am obtuse? If you somehow weight an engine to just prior to making the motor stall due to that added weight, and then ask the engine to pull 65 cars, let alone one heavyweight passenger car, up a 2% grade, how is this possible in physics? If the motor nearly stalls due to its own mass, grade or no, and then you tack on another 100 oz of drag…!?
That’s because you do not understand the methodology that he uses to add weight. What I believe he is saying is that he holds (with no downward force), or butts the engine up against an object and spins the wheels under full voltage. He then adds weight until the engine can no longer slip the drivers and then backs off on the weight. Usually, but not always, you run out of room in the interior before this happens. Since the engine is held in this manner, it is equal to the longest train that could be coupled to it, since the engine can only sit and spin.
You can do the same thing with a DMM to monitor amp draw. Using the same holding technique, monitor the max slipping current. Then add weight until you see a sudden rise in current. This rise will usually be in sync with the drivers beginning to stall. Again, back off on weight until this sudden rise is eliminated on the DMM.
Jim
Aah…got it. That does make more sense, and I appreciate your taking the time to help me to understand. I have learned something.[:)]
It does help to know the method behind the madness.[;)]
Jim
thanks guys this quit helpful. I know the engines I have and they can muster up a 2.5% grade with about 15 cars weighted about to spec. They will spin before stalling. That is why I was interested in engine weight. They do seem lite to me. Now I have a good rule of thumb to follow.
Same means I use for the maddness for a long drag. I added weights and added cars, then nail the thottle up the grade. If the GS-4’s driver’s break lose at a low setting I add weight. Added weight and try again, higher draw then breaks losse, add few more cars.
I finaly got to the GS-4 too where they could pull 21 hand picked cars but could spin the drivers when I drop the hammer up the grade. For being told the cheap Bachmann drive could not handel the weight, I am very happy with the Bachmann GS-4’s. Dollar for Dollar more fun than my BLI steamers.
Bolier Head Ken, posting again.
PS, for something that will pull great, look at PK’s E-6’s. 1 E-6 would drag a BLI backwards with traction wheels added.
bump