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Discussion Starter · #1 ·
Reading through Doug's review of Merchant Navy "Canadian Pacific" I noted that the loco seemed to have 0.6kg of hauling power. The review is here

Now this to me seemed a bit of a surprise as the Bachmann 4MT tested recently hauled 1.5kg which was the weight of a bag of flour on a low loader bogie wagon and whilst the loco struggled it did pull away. This was the equivalent of about 12 Hornby Mk1 coaches. This compared favourably with the Hornby Dublo equivalent.

In this context do any of you have issues with loco pulling power or are you all happy with what the manufacturers are offering these days?

Old Tri-ang and Tri-ang Hornby lightweight locomotives do struggle to pull more than 4 coaches but this seems to be a rare issue among todays offerings.

Traction tyres can help but of course we have lobbied for a long time to have models without traction tyres and so it is rare for recently designed locos to have these fitted.

Happy modelling
Gary
 

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DT
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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.
 

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Discussion Starter · #3 ·
QUOTE 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.

Wow!!! You can do this with DCC?


I'm a DCC thicko and so I, and many others possibly, want to know more about things like this!

And do these different settings change pulling power?

Happy modelling
Gary
 

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DT
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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.
 

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I am still a bit clueless about what is being done to get locos to drive in the same way as the prototype. I am not just thick but really thick when it comes to things like this! I am a member of the popular "plug it in and turn the knob" club!


Which control set up do you have, what button do you press, what graphs do you look at, and which knobs do you twirl?


It sounds like a good set up whatever it is. Maybe this is a discussion for the DCC area at MRF.

Happy modelling
Gary
 

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DT
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Gary, you're looking at a Bachmann EZ Command. You can't (I think) do extended CV programming.

CV's or Configuration variables hold programable data in specific memory locations in the decoder. This is permanently stored inside the decoder until the user wishes to change its value.
 

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QUOTE (Gary @ 14 Jun 2005, 07:24)I am a member of the popular "plug it in and turn the knob" club!


<{POST_SNAPBACK}>

I'm with you there Gary. I use computers for work and that's enough for me.


As far a hauling power goes. My favourite at the moment is a Hornby loco drive Princess which happily tows 11 Lima MK1 coaches around our clubs layout at a fair clip and draws only about 10 amps of power to do so.
 

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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
 

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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.
 
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