This is not going to be a blow by blow account of how to build a trolley but merely a brief description with a few pictures. It's a pretty simple trolley based on ones I've seen at various rallies and I claim no originality for the design. It was built very quickly (in about a week) as I needed one to use at a running day at North West Leicester SME's track in early July. Since then I've stripped it down again to finish it off (e.g. fit some brakes!) and give it a coat of paint. It's designed for use on raised track but could be adapted for ground level tracks by fitting a box to sit on and straight footrests instead of the long ones.

The chassis is 24" in length and constructed from 3/4" square mild steel tube of 16swg thickness all MIG welded together. It's a long time since I've done any MIG welding and it shows! Still, it doesn't look too bad now it's painted. I don't think it will fall to pieces in a hurry.

The 'buffer beams' are 1/8" steel plate again welded on. The towing brackets are bits of 3/4" x 1/8" steel angle drilled with five sets of holes so that the coupling links can be positioned to give a straight pull on multi-gauge tracks. The coupling links can also be set at different heights to suit different gauge locos. The beams extend to just above track level so that the trolley will rest on them if it derails rather than tip up (in theory anyway!)

Various views of the chassis

The suspension is by swinging arms pivotted to the chassis at the outer ends with coil springs at the inner ends, the axles being in the middle. The swinging arms are nothing fancy, just lengths of 1"x1/2" mild steel.

Underside of chassis showing anchor points for the swinging arms

and pivot pins for the brake calipers

Swinging arms

The springs need to be quite strong and the ones I've used are only temporary as they are the clutch springs from a motorbike I am rebuilding! (the only ones to hand at the time) They're a bit too short really so I turned up some spacers to make up the length required. I'll replace them with longer springs when I get chance. Each spring assembly has a bolt running through the middle anchored through the chassis at the top and a nut under the swinging arm. This holds the spring in place and stops the swinging arm dropping completely.

Springs, bolts, and spacers

The wheels and brake discs are turned from mild steel blanks rather than castings. Apart from the fact that steel seems to wear better than cast iron it works out much cheaper. All six blanks only cost £14 and there's not really any more work involved than machining castings. The only problem was that the blanks had been sawn with quite a wedge shape so a fair bit had to be machined off before they were flat! The axles are tubular and are fitted with needle roller bearings at each end which run on fixed silver steel axles. The wheels are loctited onto the tubes but the brake discs are welded on for security. Welding these was right at the limit of my welder, consequently the welds are a bit 'blobby'! The faces of the brake discs were skimmed with the wheel assemblies mounted between centres in the lathe to make sure they ran true to the axles. One wheel is drilled to take a rare earth magnet to operate a reed switch on a digital cycle speedometer which will enable me to keep a record of mileage covered by the locos pulling the trolley. I can also see how fast I'm going!

Wheel assemblies

Axles and swinging arm pivots

The footrests are simply lengths of 5/8" square by 16swg tube cut, bent, and then welded at the joints. These fit into a 3/4" square cross tube welded to the trolley chassis. Unfortunately the 5/8" square tube was slightly too big to fit straight inside the cross tube so the ends had to be ground down before they would fit easily. If I had used 18swg tube for the cross tube I think the footrests would have fitted without any grinding. I wasn't quite sure how long to make the footrests but 'guesstimated' at 12" which seems to be about right. Too long and they catch on the ground, too short and the riding position is uncomfortable.

Detachable footrests

The brakes will utilise ordinary alloy brake calipers which are easily and cheaply available for mountain bikes etc. They will be operated by a brake lever on the top 'handlebar' of the trolley. Both axles will be braked and I've got to devise some sort of compensation device to balance the braking on both pairs of calipers. I've an idea that may work using just a single inner cable to operate both sets of calipers but we will see.

Brake calipers off mountain bike etc.

08/08/2007

The trolley was quickly put back together for the rally at Little Hay but is now more or less finished.

I still need a decent piece of plywood for the top but made the chipboard one a bit more presentable by covering it with some black vinyl. A couple of lengths of aluminium angle were fastened onto the top at the back to locate the 5 litre plastic container which will serve as the water container until something better comes up. This is held in place by a strap tensioned by a spring enabling it to be quickly fitted or removed. A plastic pipe runs from the water container at the back to a valve at the front which controls the output to the loco.

Due to lack of time I only fitted one set of brake calipers but I think that is probably adequate at the moment. I don't envisage pulling loads of passengers just yet! The brake lever is a short cycle type which is originally designed to clamp around a handlebar. To fit it I cut off the round clamp and drilled the body to take a bolt which holds the lever onto the top bar of the trolley. A spring is fitted between the two brake calipers to push them apart when the brake is released but I think it may be necessary to fit some other springs to centre the calipers in the off position as at the moment they tend to be a bit lop-sided.

The bracket for the cycle speedometer simply clamps around the end of the top bar and the sensor is mounted on one of the swinging arms using small cable ties.

Side view of trolley

Front view

Sensor for speedometer

Speedo and water valve

Brake calipers

The only thing missing now is a nice soft cushion!

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