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Post by Deleted on Jun 24, 2017 13:12:17 GMT -5
Hello ...
I finished the "break in" for my Budd's and tested them together on a "rectangular" test layout (R 270mm). They run approximately the same speed, and there are no issues with the couplers. Now my problem : I tested at 5v, they seemed to be very slow ... but in fact I calculated that they were running about 60Mph ! What would be a realistic speed for Budds on a local railroad line ? 50Mph ? And for a local, "short" freight train (max 6 cars + caboose) ? 25 or 30Mph, or 50Mph too ?
Thanks for Your answers ...
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Post by markm on Jun 24, 2017 14:13:11 GMT -5
I think 50-60mph would be a safe maximum speed for both. Of course on the prototype they would slow at some crossings, or stations and turnouts, probably 40-45mph but maybe as slow as 25mph.
Mark
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Post by Deleted on Jun 24, 2017 15:39:50 GMT -5
Thank You Mark. I will now perform the break-in for my 2 GP's ; I can only decide about the voltage I will use when the layout will be finished, I must see my trains "climbing" (1.5 to 1.6%), my test "oval" is absolutely flat. But I think I won't need more than 6 to 7.5v ! The next step will be "(ply)wood-work" ...
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Post by markm on Jun 24, 2017 16:07:36 GMT -5
On my test bench I use wedges on one side to do 1% & 2% grades to estimate performance.
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Post by Deleted on Jun 25, 2017 2:36:34 GMT -5
Now I made the break-in for my two GP's (7 and 9) too. I noticed that, with the same voltage (pure DC), they run slower than the Budd's (I would say this is normal, they are dedicated to freight trains). And then with some "improvised" wedges I built a (straight) ramp of about 2% (my maximum will be 1.5 to 1.6%, with a length of 6.5m); 'cab forward' (i.e. traction tyres on the front truck) and with a train of six 33' hoppers and a caboose (one loco at a time), they slowed down but climbed the ramp. But when I uncoupled the locos, I was surprised that the cars DID NOT run the ramp down by themselves, only by gravity ; this gives a good idea of the supplementary effort needed to pull them uphill (they "brake" ) ! I hope only that climbing my ramps won't make any damage to the locos (after climbing and doing some switching, they will rest for several minutes). On my "flat" layout I didn't notice any rising of temperature after 5 minutes.
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Post by Rob Albritton on Jun 25, 2017 3:46:58 GMT -5
Now I made the break-in for my two GP's (7 and 9) too. I noticed that, with the same voltage (pure DC), they run slower than the Budd's (I would say this is normal, they are dedicated to freight trains). And then with some "improvised" wedges I built a (straight) ramp of about 2% (my maximum will be 1.5 to 1.6%, with a length of 6.5m); 'cab forward' (i.e. traction tyres on the front truck) and with a train of six 33' hoppers and a caboose (one loco at a time), they slowed down but climbed the ramp......! I hope only that climbing my ramps won't make any damage to the locos (after climbing and doing some switching, they will rest for several minutes). On my "flat" layout I didn't notice any rising of temperature after 5 minutes. 1) Because the RDC is a passenger unit, it is geared to run about 30% faster at the same voltage as our other locomotives. Although it would be prototypically unusual, if you want to run a locomotive with the RDC, the best way is to convert to DCC. 2) operations of your locomotives hauling ANY number of cars up ANY grade will not harm your locomotive. Even with the traction tires, the wheels will slip before damage is done to the motor. Note: if you add additional weight to the locomotive, then this may not be true, as the additional weight will cause more traction and strain on the motor than designed. ALSO: if the locomotive begins to spin it's wheels, make changes as soon as practical to prevent this situation. Wheel spin is a design safety to prevent damage, not a normal mode of operation. It is safe for the wheels to spin for 1 minute for every hour of operation, so you do not need to rush to correct the wheel spin.
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Post by Rob Albritton on Jun 25, 2017 3:56:22 GMT -5
Hello ... I finished the "break in" for my Budd's and tested them together on a "rectangular" test layout (R 270mm). They run approximately the same speed, and there are no issues with the couplers. Now my problem : I tested at 5v, they seemed to be very slow ... but in fact I calculated that they were running about 60Mph ! What would be a realistic speed for Budds on a local railroad line ? 50Mph ? And for a local, "short" freight train (max 6 cars + caboose) ? 25 or 30Mph, or 50Mph too ? Thanks for Your answers ... Our locomotives should start moving at no more than 3.5 volts minimum. Normal operating range for ALL of our locomotives is up to 8 volts (most will run safely up to 12 volts. Those that have a lower maximum voltage than 12 volts are clearly noted in the original packaging.) If your locomotive needs more than 3.5 volts constantly to operate, it may need an obstruction cleared from the gears and axels. Frequently this is pet hair, of long thin fibers from scenery material that wraps itself tightly around the axels and is very hard to see.
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Post by Deleted on Jun 25, 2017 7:21:06 GMT -5
To Rob : I was speaking about "subjective" speed : even running at a calculated scale speed of 60Mph, the locomotives/railcars seem rather slow. And then I made a test : all my engines start moving with two (new) alcaline AA cells in series.
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Post by Deleted on Jun 26, 2017 16:07:41 GMT -5
About "slipping" : I spoke about this problem in a former topic : I hope that constant 1.6% with curves of R=270mm minimum on a 7m ramp and 7 cars maximum (Six 33' hoppers + caboose, or four 40' box-cars + caboose) should not be a problem ; or should I modify my layout ? When it will be built then it will be too late ! I must say that I tried 2% only on a short straight track (1.2m).
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Post by Rob Albritton on Jun 26, 2017 16:20:00 GMT -5
About "slipping" : I spoke about this problem in a former topic : I hope that constant 1.6% with curves of R=270mm minimum on a 7m ramp and 7 cars maximum (Six 33' hoppers + caboose, or four 40' box-cars + caboose) should not be a problem ; or should I modify my layout ? When it will be built then it will be too late ! I must say that I tried 2% only on a short straight track (1.2m). All of our injection locomotive products are designed to function with a minimum radius curve of 195mm (7 11/16") A 1.6% grade should have a minimal impact.
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Post by Rob Albritton on Jun 26, 2017 16:25:55 GMT -5
To Rob : I was speaking about "subjective" speed : even running at a calculated scale speed of 60Mph, the locomotives/railcars seem rather slow. And then I made a test : all my engines start moving with two (new) alcaline AA cells in series. The perception of speed can be subjective, yes this is true. But the scale speed is accurate. A jet airplane flying high in the sky may not look fast because it is so small when viewed from a distance - but the actual velocity is more than 500 mph.
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Post by Deleted on Jun 26, 2017 16:39:58 GMT -5
I made the test with my 6 FT hoppers (the worst case) ; in fact they seem to be heavier than the MTL box-cars ... There is a metal bar inside. And the "load" has some weight, too. I don't know how the MTL box cars are built. I think if the train climbs a 2% slope for about 1m then it won't begin slipping several meters later ! Especially with only 1.6% .
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Post by markm on Jun 27, 2017 22:15:34 GMT -5
I don't think you'll have any problems. I haven't looked at slippage in detail, but I can give you some boundaries. A GP38-2 pulling 180 gr of freight cars (5) show no evidence of slippage on a 2% grade. The same loco noticeably slipped pulling 250 gr of Heavyweight cars (10). However this train wrapped completely around the 195mm curve and I suspect lateral forces causing the problem.
I think the major slippage issue will be the transition in and out of slopes. If it isn't a smooth transition the friction wheel can make poor contact.
Mark
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Post by Deleted on Jun 28, 2017 2:21:26 GMT -5
Thank You Mark.
The total weight of my 6 FullThrottle 33' hoppers with MTL caboose, and of the 4 MTL boxcars with caboose is less than 50g each. The maximum slope will be only 1.6% and the minimum radius 270mm. So I think there is a margin.
And the progressive transitions between ramps and horizontal parts (stations with "incoming" track) are already planned.
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