Ben from from Wentworth Falls west of Sydney was the first to have a Slo mo fitted in a

manual control locomotive. As I had no experience with manual control locos` he suggested

that I post this on my site as a guide to anyone operating manually and thinking about

installing a Slo mo


Hi Terry

Good to see you on Sunday. As expected, the Slo-mo has made a substantial
improvement to my Katie. She’s now pretty much unstoppable!


I wanted to share a few observations that have taken more than just a few days to
sink in. As you know my loco is manually-controlled. The improvements to the
consistency of her running characteristics are so profound that I’m struggling to
justify my previous plans to fit radio control.

Stan’s line is far from flat with some very significant hidden gradients on the
‘flat’ loops. Lines that are not perfectly flat (and that’s most of them!) require
drivers to make multiple adjustments to the regulator on each lap. Indeed, after a
few laps an observant driver of a manual loco can often be found waiting at each
spot on the railway where an adjustment is needed, waiting for their engine to

A fudge that sometimes works is to simply leave the regulator on a single setting
that just gets the loco over a hump, but this leaves the loco running too fast on
the majority of the line. This is why some drivers are notoriously speedy! However,
the margin for error is so slim that the loco often fails to make it over the humps
if any variable in the system changes, such as the heat of the fire, the gas
pressure, the boiler pressure, wind, etc. In effect, many lines just don’t allow for
relaxed running.

With the Slo-mo, the only time I needed to touch the loco was when I *wanted* to! If
left alone, the loco would trundle round a very rough line without any more than the
very slightest change of speed and without any driver input until the fire goes out.
The only exception to this was on Stan’s deliberately steep, long ramp that joins
his two loops (a gradient of about 1 in 30 I believe!) where the loco would
gradually fail about half-way up without a modest opening of the regulator.

Station stops and shunting have dramatically improved. Now, once the boiler is up to
pressure, I move the regulator to the position appropriate for my target speed.
Nothing happens at first as the cylinders build up the pressure required to overcome
the inertia device. This pressure is more than enough to clear condensate, so the
Slo-mo even eliminates the hydraulic lock-up that typically occurs after all but the
briefest of pauses. A glorious whooshing sound and a loud beat from the chuffer pipe
accompanies the gradual and very realistic slow acceleration until the target speed
is reached. Stopping is even more gradual but with a little practice I could easily
stop at the correct place beside a platform with a single flick of the regulator at
the right spot well in advance of the station.

The Slo-mo fundamentally minimises the benefits of converting manual locos to radio
control by improving their running characteristics in such an emphatic way. It
provides an all-mechanical solution to the at times rapid and erratic running that
can affect all locos. Provided you can reach your loco at those few times when you
want to start or stop then you just don’t need all that electronic paraphernalia
that some say detracts from the live steam experience. In this way, manual locos
have a lot to gain from inertia devices and are highly recommended.


I’m now looking long and hard at my coal-fired Robert. I’m not sure if there’s any
way to move or integrate the axle pump so that I can keep it whilst also fitting a
Slo-mo. A servo pump would be the obvious alternative, but with batteries and a
water level sensor it might become a big job plus the batteries would alter the
“mechanical purity” of the loco. I have a feeling that the Slo-mo would eliminate
the drawbacks of axle pumps and I’m keen to keep mine if I can. Perhaps I might get
you to take a look at my Robert next time.

Benjamin Xxxxxxxxxx




Matthew in japan posted this video of his Manual control Roundhouse Billy (nicely detailed)