Hi all,

I'm looking for some help with regards to building a 7.25" petrol electric loco capable of pulling passengers. I searched the forums and found the newest thread on this topic to be 10+ years old.......... feel free to link me to newer threads.

I'm a mechanic and auto electrician so am confident in the build but have no idea where to start.

With a 3 month old in the house, budget is tight!

I'm not looking to model anything in particular but I do like the look of the central qld sugar cane trains. Conveniently, boxy designs are easy (and therefore supposedly cheap to build)

I'm great with engines and electrics and am proficient with welding but have minimal access to machining equipment so would probably get that done by professionals,b ut when it comes to making a train move and, most importantly, stop i'm clueless.

I really want to do as much as I can myself as I'm quite a hands on guy and love learning as I work.

Hope I can find some help on here.

Where are you roughly?   Depending where you are, a local miniature railway would be a great start to see a loco up close. I suspect you have  all the skills needed too. Keep in touch, many would help !

I personally have no technical skills  BUT have  been with a good builder of miniature trains for a long time, and helped a little. I belong to two clubs. I have seen all his loco progress from bits of steel to finished locos.

Regards,
David Head,
Melbourne,Austalia

Where are you roughly?   Depending where you are, a local miniature railway would be a great start to see a loco up close. I suspect you have  all the skills needed too. Keep in touch, many would help !

I personally have no technical skills  BUT have  been with a good builder of miniature trains for a long time, and helped a little. I belong to two clubs. I have seen all his loco progress from bits of steel to finished locos.

Regards,
David Head,
Melbourne,Austalia

Thanks for the quick reply David!

I'm located in Brisbane and have joined my local railway which is excellent! I love going down and helping and learning but we never really have time to go over how these things are driving etc as we have 2 public ride days and a working bee every month. We have club locomotives and some guys bring their own down. I'd really like to start work on one since some of these guys have spent the best part of a decade building their scale replicas! I effectively want to make something cheap, tough and reliable. I was looking a the planet but it looks pretty pricey and also looks all electric in Australian delivered versions.

Something similar would work though.  Was going to start doing up body drawings etc to get a good feel for what I want but I definitely want petrol and electric since I know how to work on those. Would also consider petrol-hydraulic.

So have you a size of loco in mind, ie  say 4-12ft, will it be  a fixed frame loco or have bogies.

Look up the Boulder Creek Railway, there is a link/thread here somewhere and have a chat to the owner there. Also a facebook page too.

Many have built a:

petrol mechanical
petrol-electric
petrol hydraulic
diesel  hydraulic
diesal electric
diesel mechanical

many start with a 4 wheel fixed frame loco using a honda engine. Bigger usually means  a  3 Cylinder diesel, or a refurbish 4 cylinder petrol -  Mazda 323 or Datsun 180.   Seen a old holden red 186 6 cylinder engine used, and old ford prefects too

There's not a lot in terms of instructions or builds to follow, AMR is a great magazine BTW.

Not sure how to help you, hope QLD based people might speak up and offer advise.

These Facebook Groups might of use:

Live Steam & Model Engineering
Live Steamers and Model Engineers of Australia.
Victorian Miniature Railways and Model Engineering

Also worth posting the same question there too apon joining.

Might be able to  make a quick visit perhaps while in Brisbane end of May for a quick  brainstorming session -PM me if interested.

Regards,
David Head

ps I think you  might note I like the hobby and would help anyone.....

You are starting your project at a good time. By the time that you have something to run your child will be ready to drive it.

Consider a simple 4-wheel chassis. You can buy wheels ready-made from DNC ( http://www.dncsystems.dynalias.com/minirail/ ), also axles and geared motors. The hardest part is obtaining or making sprockets to suit. These could be the basis of a simple electric loco (see http://www.dazed.org/btr/BackyardRailwayDIY.pdf ) or better, a petrol-electric loco (see http://www.smex.net.au/Reference/AlternatorTraction02.php ). For electric you will have to add a heavy and possibly expensive battery, or a small battery and some paving blocks for traction. For petrol just about any four-stroke horizontal crankshaft will do. An advantage of electric transmission is that it is easy to reverse direction without a gearbox and it is easy to achieve emergency dynamic braking (rather harsh) with a big switch.

An advantage of electric (with a small battery) is that it can be made toddler friendly.

Also, do check the SMEX 7.25" page ( http://www.smex.net.au/ForSaleLS_7_AU.php ) often. Complete models are pricey but many things offered there are unfinished projects or deceased estate goods - usually not runnable but often a good source of parts like wheels and axles etc. Freight costs can spoil the bargain but every so often something interesting turns up in Qld or northern NSW.

G/day Sockie - Check out your Private Messages for some assistance.

Thanks for the comments guys!

G'day Sockie

A few extra comments regarding transmission.

At the Clare (SA) club we have a number of petrol electric locos with a hybrid engine/battery/ controller/motor drive system. Light duty car stating batteries are used charged by the petrol engine driving a truck (24V) alternator. The batteries are then connected through a 4QD controller to the motor.

Our "heritage" loco has a vertical shaft engine with a cone pulley. The driven shaft has two disk type cone pulleys and moving the engine either left or right then drives the loco in forward or reverse. Crude but simple. A source of cone pulleys would be old shearing stands.

One other possibility would be a hydraulic transmission of a ride on mower. First find a wrecked mower whose transmission still works!

Most other components are off the shelf

Good luck.

Hi Sockie,
                Easier than Electric.  6.5 hp Honda horizontal shaft electric start petrol engine, N0 7 Eaton hydrostatic motor & transmisson. I had this set up in a loco with air brakes that I once owned before moving to QLD.