A First Loco with Radio Control
Richard Gawler builds a GER Y14 and shows how to include radio control at the time of construction. Radio control allows him to enjoy running it on his friends’ layouts, as well as his own. Photograph courtesy of the Ilford and West Essex Model Railway Club
As a newcomer to O gauge, I soon found myself wanting to build a reasonably universal loco I could run on friends’ garden railways, club layouts and test tracks, as well as at home. Radio control with battery power seemed like a sensible thing to try because this would create a model without commitment to the local control system, be it stud contact, third rail, or analogue or DCC two-rail.
My own layout will represent a light railway with one engine in steam. As a spin-off, the use of battery power lets me build a layout with very simple analogue wiring and then introduce a second loco without recourse to section switches.
I like the idea of a loco carrying its own source of energy, especially on a lengthy garden railway. The only alternative I could think of was clockwork and so I made a start by buying a kit for a LNER J15 from Connoisseur Models. I wanted an exit route if radio control turned out to be impractical, so I also bought the 40:1 gear set recommended for the loco and a 12-volt Canon motor.
Preparation and design decisions
My first practical activity was a field trip to Sheringham to see the preserved J15, formerly BR number 65462 and now restored to resemble a Y14. As it happens, I found myself sharing a compartment with a modeller who does 16 mm live steam, and before we reached Holt I had decided to use an entry-level Omni system from Fosworks for my project.
I reached the detailed specification of the control system during a telephone call to Steve Foss, the proprietor of Fosworks. The most important decision was the style of the battery pack, which would use AAA size NiMh (rechargeable) cells arranged across the width of the tender. Each cell provides about 1.2 volts. I did not expect to run the motor from a full 12 volts, and I knew that an odd number of cells would pack together into a smaller space than an even number, so I specified nine cells for the battery pack.
On receipt, the radio control equipment for the loco looked like this (right). Clockwise from the left there is the battery pack and its safety cutout; a charging socket and changeover switch; the control board with its output wires to connect to the motor; and the radio receiver. The switch selects between charging and running, and the ferrite bead on the motor wires (hidden inside black sleeving here) suppresses electrical noise passing from the motor back towards the control board.
The radio communications use the 2.4 GHz band. The radio receiver connects to the control board, which provides the power output for the motor. This particular control board supports three different profiles for motor control, and one of these gives a pleasant slow start operation with my loco.
I put quite a lot of planning into the build before I began, to let me adapt the kit to represent a Y14 and to accommodate the control equipment.
Looking back, I think the most important thing helping me here was the knowledge passed on by many modellers that this kit goes together without any problems. Life would have been much more difficult if I had needed to make new parts to compensate for shortcomings in the design of the kit.
My main design decisions were the following:
- Battery pack placed across the width of the tender and supported by a false floor
- All control equipment inside the tender
- Radio reception using the aerial built into the receiver
- Charging socket and control switch accessible when the model is on the track
- A plug and socket under the loco to connect the wires from the tender
- Provision to add conventional pickups to the tender wheels.
I made all of these decisions before I started to build the model. I find it too easy to succumb to “feature creep” in this sort of project. I thought about having a multi-way changeover switch in the tender, so the loco could recharge from the track power, or run from track power, or even put its own controlled voltage onto the track to drive other locos. I thought about an LED in the firebox, to act as a ‘power on’ indicator, and an illuminated tail lamp on the tender to do the same. None of these happened, and I am sure simpler is better.
It was sensible to make the electrics as simple as I possibly could; there was plenty of work in building the model.
I allowed myself one luxury and one extra precaution. The luxury is a branded toggle switch in place of the budget one supplied with the control equipment. The extra precaution is a cartridge fuse between the controller output and the motor. I know that the motor is unlikely to fail as a short circuit, but the fuse gives me a little peace of mind.
Equipping the GER Y14 and its S23 tender
I started the model making by modifying several parts of the tender to let it hold all of the radio control equipment. In particular, I built the tender as three subassemblies instead of two, with a separate body and footplate as well as a separate chassis.
I placed the main parts of the radio control
equipment on the tender footplate to get an idea
of the amount of space available. There is
enough space inside the tender chassis to hold
the control board, but putting everything into the
body gave me shorter wiring.
I modified the sides and floor of the coal space
to make room for the two circuit boards
underneath.
I built the tender body working from the top
down, which is the opposite direction to that
suggested in the instructions for the kit. I cut
some slots in the floor of the coal space to help
the radio communications to work
The false floor to hold the battery pack is from
0.45 mm brass sheet and angled carefully to let
the battery pack slide into place.
The charging socket fits inside the envelope of
the tender body, but the solder tags and wiring
on the toggle switch descend into the chassis
assembly below.
The charging socket and the toggle switch are
easy to reach without lifting the model off the
track. The coal will hide them after the model is
finished.
I omitted two of the frame spacers for the
tender chassis and added a floor made from
sheet brass. This created a tray-like space to hold
a tag board with a fuse. The large hole in the floor
is a provision for wiring to pick-ups on the tender
wheels, in case I abandon radio control or try to
charge the battery from the track. Before starting
assembly, I also cut a hole in the front-most
spacer to let me take the two motor wires out
horizontally to the loco.
I built the tender footplate as a self-contained
subassembly. This is sandwiched between the
tender body and the tender chassis in the
finished model.
With all of the radio control equipment going
into the tender, the modifications to the loco were
minimal. Before I built the chassis, I cut a narrow slot in the rearmost frame spacer to accept the
four pins of a Molex power connector. These
connect to a piece of stripboard on the other side
of the frame spacer. I cut smaller slots in the
adjacent spacer to accept the wiring to the motor,
and filled the mounting holes for plunger
pickups.
The completed radio control installation
includes two wires from the tender to the loco.
PVC is difficult to paint so I chose brown
insulation as a gesture towards the grime found
on the pipes near here on the prototype.
The build progressed well, and the completed
model had many test runs. The performance of
the loco and its control system rather exceeded
expectations and I added no extra ballast weight
inside the loco. Eventually, I dismantled the
model for painting.
The wiring inside the loco is straightforward,
with just two wires from the Molex connector to
the motor. I turned down the middle of the rear
axle to make a clearance in front of the
stripboard, and this was the only unplanned
structural alteration needed during the build
Compare the S23
tender with the tender
on a Britannia class
loco, to see just how
much more space there
is in the later prototype.
The BR1 tender offers
room to include a
sound system as well.
Conclusions and ideas for further work
The main outcomes from this project for me are the joy of owning a loco which runs well and never stalls, a wireless remote control, and the ability to run a second loco without the complexity of DCC. My decision to use nine 1.2- volt cells was a bit of a guess, but the loco achieves a scale speed of around 25mph and this seems just right for a Victorian freight train.
I still do not know the endurance of the battery pack, but it is more than four hours. If I ever have a garden railway of my own, I can build it as a dead track system and have no concerns about voltage drop.
Putting the receiver inside a metal box (the brass tender) reduces the maximum range for radio communications, but I have obtained reliable control over a distance of 100 metres, this trial being done in open countryside with an electrically quiet environment. I cut three slots in the floor of the coal space to help the radio communications to work, but subsequent experiments suggest I only really needed one.
All of the control equipment inside the tender connects together using plugs and sockets except for the soldered joints on the tag board. This construction will help me if I ever have to renew the battery pack.
The chosen controller has no overload protection on its output. It is therefore most unwise to try to use the controller to provide power to the rails because any short circuit on the track could cause irreparable damage to the controller.
My completed loco has no additional ballast weight and spins its wheels (and does not stall) when presented with a train too heavy for it to pull. This seems sensible for all solutions but may be impractical for a tank loco weighed down by a battery pack.
The only real downside I have found is, if I pick up the loco from the track when it is running, the wheels continue to turn. I am not used to this. After trapping a finger between side rod and footplate and enduring agonising pain until I could turn off the throttle with my spare hand, I have not done this again.
It is interesting to compare the S23 tender with the tender on a Britannia class loco, to see just how much more space there is in the later prototype. The BR1 tender offers room to include a sound system as well.
When I started this project, I knew nothing about radio control for model railways and I bought a control system complete with all of the necessary wiring harnesses. These turned out to be too bulky for my modest S23 tender and so I made some new wiring.
The GER used the S23 tender with other locos including the E4. If I want to build an E4 (or perhaps a later Y14), I could reuse my tender and couple it up to the new loco.
Preparing for a fresh
outing. The control
equipment supplied by
Fosworks includes this
charger for the battery
pack and the handheld transmitter.
I want to try something different for my next loco, so I expect I will buy a receiver and controller, make my own wiring harnesses, and of course re-use my existing transmitter and charger. I will be happy with a running time of two hours rather than four, so I can investigate use of a 6-volt motor with fewer or smaller batteries.
I am already enjoying my loco. One day I will give it a cab interior and a crew, and some coal in the tender. I have the cab side plates on order and I expect I will add these next. Many friends, acquaintances and members of the Guild have helped me during this project, and my thanks go to those who gave me the use of their layouts and test tracks during performance testing and running in; and offered encouragement and ideas to keep the build rolling along.
There is a slideshow of this build, it can be found at GER Y14 (1891) construction. This begins with the tender (where Richard did most of the r/c work) and only lasts two minutes.
The Chosen Prototype
Unlike the planning for the radio control installation, the design specification for the model rather evolved as I went along. I was fortunate to have some essays by Lyn D Brooks published by the Great Eastern Society, who described the variations between Y14 prototypes of different batches. It was easy enough to think through the alterations I could make to the kit to suit many of these, but perhaps inevitably I built what I could do with a minimum of extra work.
For me, this was to procure some tender side frames with D-shaped cutouts to represent an earlier tender (these frames were spares from an Alan Gibson kit); and provide a new cab roof, smokebox door, lubricator and minor details. I omitted many kit parts including the steam brake (added by 1900), the smokebox wrapper (added by the LNER) and the fittings for a train brake. This let me reproduce a loco from batch S.28 (built 1891-2) in its original condition.
The painting and lining is by
Warren Haywood.
