Realistic speed for trains in the 50's.

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" ...

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.

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.

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).

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.

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