Loco hauling power

I loaded a few goods waggons with weight until the loco ground to a halt, then weighed the load including the waggons and converted it into Newtons - which is the correct unit of measure for pulling force (at least for small things).

I also program the chips to represent what I think are realistic top speeds and power curves (lower and middle speeds too) for the locos. I'm not sure if this alters the pulling power. Basically I figure that as the A4 was the fastest steam loco, it gets top speed on my track. The Merchant Navy Class a bit less and the goods locos less still.

Perhaps one day we could get a table of speeds together for various locos to do it more scientifically, but for now the speeds look fine.

I'll double check later on to see exactly how many coaches this translates too as I have been building up my collection recently and now have a good number to test.

You can program the voltage for each step if you like to determine the shape of the power curve. For each loco and type of loco it will vary.

A simple way to do it is to use CV5 (top speed or voltage at the top speed step), CV2 (low speed or voltage at step 1). This creates a straight line speed gradient. Setting CV6 (Mid-point speed or voltage at middle step) allows you to define the shape of the curve - either convex or concave. Most locos would have a convex shaped speed curve.



So I re-tested the Merchant Navy class with coaches. It pulled 6 Northumbrian 'Blood & Custard' coaches which are quite heavy at about 150 grams each, plus 4 older style Gresley teak coaches that weigh 130 grams each. I added two more Gresleys, but the loco slipped all the way around the track and stopped on any gradient.

Overall it can pull 1.42 kg (10 coaches). When I measured this before, I think I may have put the weight in too few waggons before and therefore didn't spread the load enough.

Gary

My DCC has a button which sets inertia in steps 0 to 9, providing you have a smooth starting and running loco, winding the control will result in the loco starting slowly and accelerating to whatever you have set on the speed control, similarly it will also decelerate gradually to a stop with no input from the operator. My H0 SD-45 takes about 6 ft to stop when set to 9, a bit of a b****r when you come to a terminus and misjudge it. By just pressing the fwd/reverse button you get a gradual stop followed by a similar slow change in the opposite direction. This can be programmed in but it is more convenient to be able to select it from your controller, I usually have mine set to 5.

For someone who has trouble with his mobile phone and VCR I find DCC programming quite straight forward.

Must rush off now as I have a cheapo live chassis B23 awaiting surgery to fit a decoder.

Brian

I find the newer loco drive hornby stuff to be a very mixed bag varying from loco to loco. I have 2 spam cans one of which slips on every curve with a few coaches on the other hardly notices the load at all.

I tested my new A4 with the 6 coach northumbrian rake on which it hauled superbly, I then thought i'd give it a real test and stuck my other 5 coaches on to match, the poor thing did try but nearly ground to a halt on the first bend. Also I dislike the new type coupling as with that many coaches on the front pair become like elastic bands on curves and they tended to derail with the weight.
The absence of traction tyres may be a big jump forward but nickel-silver wheels on nickel-silver track seem to be a slippery combination.

Just as another comparison I tested my old tender drive Mallard before selling it and it seemed to be either stopped or flat out with very little in between, the slow running characteristics of the newer one are excellent by comparison.
Perhaps my next experiment will be A4, A3 and A1 to see if these are as varied as the bulleids were.