Powered Bogies

can you post a link to 'SMEX', google doesn't find it? The figures you quote seem a bit low but in the right ballpark. The gradient resistance for your 1260kg (100+2*100+12*80) train is 25.2 kg, leaving only 1.8 kg (1/700 of train mass) for rolling resistance. This is very low, you can't freewheel down a 1:700 slope, you can down 1:100. It makes very little difference as the gradient resistance dominates.

Hi Dave,

Thanks for that, a lot of interesting and useful information and you are quite correct the design is a challenge. To the best of my knowledge there are no reference books that you can turn to and find all the answers. My 0-4-0 is a mix of what I,ve seen, what I,ve read, a bit of guess work and gut feeling. I am quite confident it will work but to what level I dont quite know. To be honest I dont really care too much as long as it doesnt really struggle along and is only capable of pulling one person, but I,m hopeful it will be better than that.

Its certainly been an interesting challenge starting with a blank piece of paper and I think I have learnt quite a lot. I guess it is a test bed really, finding what works and what does not and I will be better prepared for the build of the larger loco.

I think you have also answered Kaleb,s question as to using a single 24 volt 500 watt motor to haul 5 persons, sounds as if he should be fine.

Regards

Ron

The link to the SMEX Rolling Resistance calculator:

http://www.smex.net.au/Reference/RollingResistance02.php

So since we're basically all in conclusion a single 24v 500w motor will do the trick then the problem just becomes I'll need to be mounting the motor perpendicular to the axle(s) due to size constraints. Aside from the possibly drive shaft idea as mentioned earlier, does anyone have any better ideas??

Also just like to say thanks to everyone for the help, the wealth of knowledge here is astounding!

Hi Kaleb

Thanks for the link to the SMEX rolling resistance calculator, that will be useful and should certainly help put a design in the right ballpark.

Ron

In the 1989 ME article the drive is via bevel gears and chains, the gears came from a hand drill. The generator/motor is a 12V one but run on 24V. The only trouble is that these genies are getting scarce.

Ian S C

I'm using the gearbox from a 240V 2200W Makita 225mm angle grinder for my loco. Mine's a petrol engine but no reason you can't hook it up to your electric motor. Added benefit is build quality plus built-in speed reduction of about 4.5:1 and right-angle drive in a unit compact enough to easily fit between wheels of 5" gauge loco.

Suitable second-hand angle grinder off e-bay or similar should be relatively easy to find. Maybe also check builders equipment hire firms for disposal of broken ones as well.

Hi Kaleb

You mention mounting the motor perpendicular to the axles, with drive shafts/gears etc you obviously can but why are you having to mount the motor at 90 degrees to the axles..? What are the dimensions of the motor you are  considering..? Also what are your ideas with regards to the the pivot movement of the bogies and the drive..?

Sorry this sounds like an interrogation but its not, its the same design problems I have been considering for when I start the twin bogie class 22. I do think though, with twin bogies 2 motors makes life easier with a motor fixed to each bogie, and the motor can be mounted parallel to the axles using either a gear or chain drive.

Regards

Ron

Edited By Ron Laden on 09/07/2018 13:34:39

Hi Ian,
Is it possible you could post a scan or a photo of that article in this thread?
Cheers

Hi Ron,

The motor I'm planning on using is a 24v 500w DC motor with a overall length of 263mm and a width of 126mm. As I mentioned earlier Im basing the design of the locomotive from a 1954 Baldwin 0-4-4-0 diesel-electric switcher and so the sketches I'm working to means the width of the body (I'm unsure of exactly what to call the area but the other end of the locomotive opposite to the cab end) is only 150mm to scale so I can either use some smaller motors which will create more headaches or I can run that motor perpendicular to the axles and make that just run a driveshaft.

To clarify and save answering later, I plan on putting a 2-stroke motor in the cab area which will run a 24v alternator thus if I was to use a electric motor on each bogie it'd make things rather compact which is still doable but I feel as the driveshaft idea may be easier if I'm to get power to both bogies.

As for making the pivot movement so far the best I can come up with is using a hollow tube for the pivot then from the driveshaft putting a mitre gear (or the 90 degree angle grinder gearbox) over the centre of the pivot which would then run a shaft down the pivot to another mitre gear on the bogie which would then run parallel to the axles so then run a chain to the axles. I'm sure that could've been explained easier but I hope you get the idea, I haven't got the sketches with me currently so it makes explaining it a little difficult.
but the idea for running a shaft down the centre of the pivot point isn't concrete yet so if anyones got a better idea then be my guest,

Regards, Kaleb

This is the arrangement I used on my loco, used standard angle grinder gears. Plan to swap a poly vee or toothed belt for the spur gears

Hi Kaleb,

I built a Toby Tram back 14 or 15 years ago. I got the construction article from the Australian Model Engineer. I changed a couple of thing, changed to 24 volts & 24 volt motor mounted vertically in the center of the axels. Coupled this to a 4” angle grinder head. The motor is 5000 rpm max, the grinder head has a 4 to 1 reduction, from memory! I then further reduced this 2:1 to the rear axel, with 1:1 to the front, chain drive grinder to axel, and axel to axel. Coupled it up this way so that when running forward the coupling chain tightens up & lifts to give more ground clearance for ground level running.

He’s run many happy kilometers! I can post some pictures of the motor mount etc if you are interested.

Cheers Kerrin

Long ago we built a 10 1/4" garden railway using cut down 2' gauge skip wagon wheel sets. This was powered by a Lucas C40 dynamo with the field rewound to operate as a series motor. Drive was by a V belt to a countershaft and chains to the wheels. The line was fairly level. With a driver and four passengers consumption was 10A at 24V (240W) Starting current was around 25A with a simple 2 step resistance controller.

When PSME had a track, one visiting loco used two vertically mounted Lucas C40 dyamos as traction motors.

I I R C the bevel gear pinions and crownwheels came from small hand drills.

Howard

Hi Kerrin,
That sounds really interesting how much of can he pull? and sure photos of it all would help significantly!
cheers, Kaleb

Hi Kaleb,

Sorry for the delay in replying work, life & the universe got in the way! If you have a look in my album I've upload some photos of how I mounted the motor & gearbox, hopefully they are helpful. Happy to answer any question.

Cheers Kerrin

Hi Kerrin,

I noticed in the photo of the underside of your toby locomotive you've got the grinder head mounted straight onto the underside of the chassis. Do you have any problems with tension between the grinder head and that axle?

Regards, Kaleb

A question for everyone is the steel used for bogies and the Axle boxes what type of steel is best for them? Is regular black mild steel ok for them? Or would it be better to use a tool steel or such? Any information helps.

Regards, Kaleb

I used black mild steel for my chassis frames, with horns built up from hot-rolled mild steel angle and strip, and axleboxes made from zinc alloy which house sealed ball bearings which the axles run in. The zinc alloy is self-lubricating when running against the steel horns. Just make sure all your sliding surfaces have a good finish.

I retained the gearbox housing from my angle grinder to keep the shafts in correct alignment. The gearbox floats on the drive axle and has a torque arm formed by an extension to the gearbox which contains the input drive shaft from the motor. This torque arm is attached to a chassis cross-member with flexible rubber mounts. The drive shaft from the motor has universal joints to compensate for any movement of the axle on its suspension. The universal joints are modified from those made for use with square drive socket sets. I've used 3/8" ones. Don't have any decent photos of the setup, sorry.

Hi Kaleb,

No problems at all with the setup. I'd have to flip him on his side to check but there may be a half link in the chain to get the spacing correct. I seem to remember spending a bit of time sorting out the distance between the sprockets. A friend worked for a supplier, which is were I got the chain & sprockets, so had the info required to sort out the distance. The springs are reasonably firm so probably not a lot of movement.

Re your other question on frames etc. Tobys frames are mild steel, as are the axel boxes & they ride face to the frames, horns are 12mm key steel from memory & only because its nice & square! Drilled a hole in the frames & put a squirt of oil in ....when I remember!

Just reading Perko7's post & version 2 of the coupling between the motor & angle grinder head is a 3/8 universal joint, I kept the socket end, drove out the pin on the spigot end, modified a 11 mm socket...use the 6 point one....I started out using a 12 point one & it was starting to show signs of wear...& pinned it back in place. Only reason I used 11 mm was I've got a bunch of hex that size. I milled the motor shaft to fit the 3/8 socket end & located a short length on the hex to the grinder head. Lots of km's & no issue!!

Cheers Kerrin