First Foray Into RC - French Metre Gauge

[MickRalph]

I am currently building stock for a projected layout based on the metre-gauge Tramways of the Correze (TC) in France.  As I also model the LSWR in P4 gauge, I am making the models to 1:55 scale on P4 trackwork.  This means that I have to make everything myself.

Over the years, the TC ran several types of autorails (railcars), the early ones being single-ended, meaning that they had to be turned at the end of the trip.  There wasn’t always a turntable available, so that the autorails had a mechanism which could be wound down to engage the track (this is not my model)

 

 

and the autorail could then be turned by the driver applying his shoulder to the body, as here:

 

Thinking about how to replicate this in model form, it occurred to me that this could be done using RC to control a servo or a small motor to raise the autorail off the track.  I would then use a model figure attached to a wire to replicate the driver turning the vehicle, before the servo operates in reverse to lower the vehicle.  I guess that a second servo/motor could be arranged to turn the autorail through 180 degrees, rather than use a model figure.

As I will be incurring the expense of  Tx and Rx modules, I will also power the railcar through the RC system.  The first couple of railcars that I am making will be powered by the High Level Kits “Pacer” gearbox, with a Mashima 1020 motor.  For a later model, I have just found that Hollywood Foundries do a replacement chassis for the Dapol Park Royal railbus and the chassis of this is just about right for my autorail. Also, I have drawn up plans for a pair of the 0-6-0 Piguet locos which the TC ran and I also plan to power these by RC.

The TC was a true tramway, and the trains ran through the main streets of the towns and villages.  It would be great to run the trains alongside some motorised road vehicles as they run up a hill and through the town square to reach the station.  This has just a passing loop and one siding, with an engine shed on a second spur off the end of the loop.

On the RC side, having read the various threads here and on NGRM Online (and Dead Rails in the US), I am planning to use Deltang items, purchased through Micron.

I propose to buy the Tx22 transmitter, as I will have several vehicles to control, and will use the Rx61-22 receiver.  For the battery, I intend to buy the Hyperion G3 CK 240MaH Lipo, together with the E-flite Celectra 0.1-0.7A 1S LiPo charger.  I will also buy a Pololu 9v booster in case I need more voltage than the 1S battery can provide. Additionally, I will need a charging socket and lead and an on/off/charger switch and, I think, some additional leads and sockets. I intend to get some LEDs for the front and rear lights of the railcars.

I would welcome any comments on these intended purchases.  One thing I am not sure about is what would be an appropriate servo to buy; this will have to do more than those used in steering road vehicles, as it will have to lift the weight of the railcar (which will have to be well-balanced over the centre of the lifting device.  The railcars will be quite light, being constructed from plasticard, but I suspect that small servos will not have the torque to lift the weight of them.  I would thus welcome suggestions for a suitable servo.

Mick Ralph
 

[Joseph_Pestell]

I can't help you on the technical stuff. But just wanted to say what a great project. Look forward to seeing it.

 

The Hedjaz Railway in Syria also had some DeDion (?) railcars with these integral turntables.

[BG John]

On ....... NGRM Online

Presumably you're following Daniel's Pot Pourri then. There's so much tempting stuff!

[fallen]

Hi Mick,

 

My this sounds an interesting idea! I like the idea of the figure pushing it round, and am wondering about lining it up above the tracks before lowering it. Maybe some "planks" alongside the rails to guide the wheels?

 

Your ideas on the control system look good to me. I can't comment on the LiPo as I don't know what current and voltage your motor would need but it should be OK if you do not need the step up circuit. If you do you might need a bigger capacity.

 

The Rx will need programming to give the servo outputs I think, I suggest you talk to Micron about this as they should be able to set these up before they send them to you.

 

As for servos, have you looked at linear servos eg

http://www.micronradiocontrol.co.uk/servo.html#sm-os1300

 

These may be more suitable for a straight lift if you can fit one in.

 

Frank

[Robin2]

If you use a low voltage motor you won't need the waste space and waste energy of a voltage step-up. Cheap servos are a good source of low voltage motors - probably a lot cheaper than Mashima. If you have enough space for what is usually referred to as a 130 sized motor then they are readily available for about £1.50. The problem is to know the voltage they are designed for.

 

...R

[BG John]

If you use a low voltage motor you won't need the waste space and waste energy of a voltage step-up. Cheap servos are a good source of low voltage motors - probably a lot cheaper than Mashima. If you have enough space for what is usually referred to as a 130 sized motor then they are readily available for about £1.50. The problem is to know the voltage they are designed for.

 

...R

The ones I've bought on eBay have been advertised as 3 or 6 volt. The details of the 3 volt ones quote a range of 1.5 to 4.5 volts, and I think the 6 volt ones are up to 9 volts. I haven't tried any of them yet. As they look identical, I mark the voltage on the case with permanent marker.

[Robin2]

 As they look identical, I mark the voltage on the case with permanent marker.

I tried that too. But I found that it rubs off so now I scratch them with a sharp point. If only I could remember what the scratches mean ...

 

...R

[BG John]

I tried that too. But I found that it rubs off so now I scratch them with a sharp point. If only I could remember what the scratches mean ...

 

...R

I like the way that permanent marker isn't always permanent! I marked up the rails on a couple of Peco points I was going to convert into a Barry Slip in a variety of colours. I'm about to lay one of them unaltered, and no doubt loco wheels will wear the pretty colours off.

[MickRalph]

Thanks everyone for your comments.

 

Presumably you're following Daniel's Pot Pourri then. There's so much tempting stuff!

I love Daniel's contributions to the NGRM forum, but I had missed this one - I will have to have a close look.

 

@Fallen - thanks Frank for the suggestions; I plan to buy some alternative items so that I can do some testing.  I haven't tested to see what amperage the motor consumes, nor its starting voltage.  I was planning to ask Micron to preconfigure the Rx and to add the wires for the servo and lights.  I hadn't thought about a linear servo, which would seem to be better for my purposes, but, as an RC beginner, I am worried that it may not be powerful enough - the spec for the Micron ones  says 35 or 45gm force.  I will raise this with Micron and can also buy a larger servo which would do for operating points.  BTW, I have been very inspired by your contributions on NGRM Online.

 

@Robin2 - I had already bought the Mashima motors and gearboxes before I thought of going RC, but I also have some Nigel Lawton 6v motors and gears, bought for some locos for the Torrington & Marland clay line which ran into the Torrington standard gauge station, but which I haven't got round to building, so I can try this too.

 

Mick

[Joseph_Pestell]

A couple of days ago, someone highlighted a source of slow motors with gear boxes giving just 2rpm (or even less). If combined with a cam, that could give you the lift movement that you need.

[MickRalph]

Having done some more reading and had an email correspondence with Andy at Micron, I have ordered a Tx22, two Rx61s and an Rx41, together with 3 Lipo batteries, a charger and an 8v booster; also various wires, switches, LEDs and connectors.

 

I am now turning my mind to how to replicate the operation of the internal turntable mechanism carried by the railcars.  I had thought that I might use a linear servo mounted vertically to give the vertical lift to the mechanism, but Andy thinks that these servos would not have enough power to lift the weight of the railcar, and would anyway be too fast-acting.

 

Andy suggested that a motor driving a lead screw might be the answer, so I then wondered whether I could mount a screw thread into the turntable mechanism and fix a nut into a bevel gear, with the second gear being mounted on the shaft of a micromotor.  I have thus ordered a Solarbotics 30RPM 6v motor.  However, it occurs to me that I will need a second ESC to drive this motor, but the Rx only have the one to drive the main motor.  Would I need a separate Rx for the turntable motor, to be bound to the Tx?  Could the ADD2 module be added to the existing Rx to provide a second H output, and if so how is the speed controlled for this output?

 

I am also wondering whether the Fusion Servo Slow could be used to slow down a conventional servo to provide the vertical lift needed?  It would obviously be powerful enough.

 

I would welcome any suggestions as to best way to achieve the necessary lifting action.

 

Mick

Edited October 1, 2017 by MickRalph

[BG John]

Does the Rx have any PWM outputs? If so, you could buy a separate H-bridge motor driver for it, from around 99p from China, or several pounds from a UK supplier.

[Spotlc]

I am also wondering whether the Fusion Servo Slow could be used to slow down a conventional servo to provide the vertical lift needed?  It would obviously be powerful enough.

 

I would welcome any suggestions as to best way to achieve the necessary lifting action.

 

Mick

An interesting project, not without it's challenges!  

 

If I were doing this I think I'd look carefully at the possibility of using the lens advance/focussing mechanism from a small defunct digital camera - something like an old Canon Ixus V2 is very tiny, and all the mechanics have been done for you, although working out how to control it might be interesting! Space might be another problem!

 

There are still a few vestiges of the TC metre gauge line visible in Tulle station, or at least there were when I was last there, a couple of years ago, and further north, the metre gauge Chemin de Fer de Blanc-Argent is alive and well, and the ride from Salbris to Valençay is enchanting!

 

Mike

[Robin2]

 However, it occurs to me that I will need a second ESC to drive this motor, but the Rx only have the one to drive the main motor.

It's a long time since I used my Deltang stuff. I can't remember if it can drive an external h-bridge such as the Pololu DRV8833.

 

And it would be worth studying how all the motors in this crane are controlled

 

...R

[MickRalph]

Several of the stations on the TC have been restored and there is a 50?mile long waymarked auto route from Tulle to Ussel passing each of the stations; also you can buy a pack with details of a long distance footpath using the route of the TC where possible.  I will be over there in 10 days time to do some decorating in our house and close it up for the winter.

 

It was Giles' thread on the lorries and crane which first attracted me to RC.  I re-read the thread, but he didn't give details of how the winch and slew motors are wired.  I spent a long time watching them in operation at Aylesbury earlier this year.  I will send him a PM later in case he doesn't see this thread.

 

I will report any progress in due course, when the various bits of kit arrive.

 

Mick