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## RE:Gradients in Z gauge

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• Selecting gradients is fraught with difficulty ! What s acceptable on a straight stretch of track will not work on a rising curve and similarly, the type of
Message 1 of 2 , Jun 3 12:08 PM
Selecting gradients is fraught with difficulty !

What's acceptable on a straight stretch of track will not
work on a rising curve and similarly, the type of locomotive
and rolling stock used effects the maximum acceptable

I started by using the same gradients as I have successfully
employed with an HO layout but these proved too steep for Z.
This is almost certainly because I was using weighty Swiss
Hag locomotives in HO which have powerful motors, metal
bodywork and traction tyres fitted. None of my Marklin Z
locomotives have traction tyres.

What's certain in Z as with every other gauge is that a much
steeper gradient can be used on straight track than on a
curve. Similarly, a train with two axle rolling stock seems
to take a gradient better than one with four axle bogey
coaches or wagons.

Using Marklin standard radii curves and my own locomotives
and rolling stock I can certainly confirm that a gradient of
2.5% is too steep and will cause wheel slip with most
lengths of train. The same gradient on a straight is OK,
however.

The only way to be sure is to experiment with your own
equipment and see what works.

Don't forget when designing your layout, it's very easy to
forget that if you are looking to loop one track under
another you can halve the gradient required to reach a
clearance height if you make the lower track go down at the
same rate as the upper track climbs !

Conventional thinking means a layout with three track levels
is built off a flat board where track level one is flat on
the board and everything else is above it.

When I design a layout with three track levels, I make the
"baseboard" height the middle one and construct the layout
on an open frame. That way, in Z gauge, track level 1 might
be at an altitude of minus 25mm and track level three at an
altitude of + 25mm. Each track is on a shaped track bed of
it's own at an individual height above the frame. Only the
lowest point of the bottom level track bed might sit
directly in the frame. That way even the lowest track can
descend to pass under another track that is ascending.

Chris Sheldrake
• Hello Chris, ... We want to do more in a small space -- unfortunately we cannot just scale down standards from another scale and expect them to work for Z
Message 2 of 2 , Jun 4 7:03 AM
Hello Chris,

Chris Sheldrake wrote:

> Selecting gradients is fraught with difficulty !

We want to do more in a small space -- unfortunately we cannot just
scale down standards from another scale and expect them to work
for Z scale. Our engines are lighter and even the slightest differences
in track height and gauge can derail a train. The tolerances kick in.

> SNIP>
>
> Using Marklin standard radii curves and my own locomotives
> and rolling stock I can certainly confirm that a gradient of
> 2.5% is too steep and will cause wheel slip with most
> lengths of train. The same gradient on a straight is OK,
> however.

A 2.5% grade will work fine as long as you use much larger radius
standards than Marklin has and make sure that you have built in
easements for both the approaching grade and curve. I try to think
outside the Marklin track box. As for wheel slippage, just double
header your locos along the grades and it will look even more
prototypical.

> SNIP>
>
> When I design a layout with three track levels, I make the
> "baseboard" height the middle one and construct the layout
> on an open frame. That way, in Z gauge, track level 1 might
> be at an altitude of minus 25mm and track level three at an
> altitude of + 25mm. Each track is on a shaped track bed of
> it's own at an individual height above the frame. Only the
> lowest point of the bottom level track bed might sit
> directly in the frame. That way even the lowest track can
> descend to pass under another track that is ascending.

I must admit that the "base" level of any complex layout should always
have it's zero datum elevation at least 2" above the plywood base. This
is to allow for drainage and creeks, etc. and perhaps an occasional
"dip"
under a crossover loop. --Reynard

>
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> Chris Sheldrake
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