Heaviest 7-1/4" Engine?

 
  TomBTR Chief Train Controller

Location: near Sydney
We are looking at rebuilding a bridge at our club track. We could just replace the stringers with similar sized second-hand hardwood or we could design something more precise. If the latter it would be good to know that the line could carry any engine that someone might bring on a trailer. There are many spans, each about 1 metre clear.

Most engines weigh less than our fully loaded passenger cars for which we allow about 600kg. A scale model of a 20 ton cane tram engine should weigh about 560kg without the driver. However not all engines are to scale and some can carry a lot of water. Very large ride-in diesels are unlikely to be a problem as only one bogie could be on each span at a time.

The question therefore is what is the heaviest load we are likely to encounter over a one metre span?

Thanks

Tom

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  neillfarmer Chief Train Controller

I think you are over thinking this. Why not just choose a mass that is well over anything expected and build it to that, eg. 1000kg. For a 1 metre span the additional structure is not going to be great. Call the additional steel corrosion allowance.
  RTT_Rules Oliver Bullied, CME

Location: Dubai UAE
I think you are over thinking this. Why not just choose a mass that is well over anything expected and build it to that, eg. 1000kg. For a 1 metre span the additional structure is not going to be great. Call the additional steel corrosion allowance.
neillfarmer
Yeah, tend to agree.

A few years back I built a series of timber bridges around my dam in Gladstone. The first one was with left over outdoor grade treated pine meant to be used in a deck. I built a 6m long box girder bridge, single span. The size of the box girder were 1m x 1m. Basically a copy of the Boyne River Railway Bridge style common in railways from 100 years ago, both timber and steel.

I used to drive my Ride-on mower - JD, 230kg + me + fully loaded trailer full of dirt another 200-300kg. The bridge didn't even creak. I did not engineer it.

I think the most important part s to spread the weight. Your axles will have around 150-200kg load max, just spread it across a few spans.

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