Hi Folks

My first post to your extraordinary site...so impressed...thanks.

'Shakamaker' from 'Trainorders.com' in 2001 wrote...

**"BHP Iron Ore in the north west of Australia ran the worlds heaviest ( and possibly longest) train on Thursday evening. **

The train was powered by 8 AC 6000hp locos and weighed in at a staggering 82,000 wet metric tonnes + tare weight of vehicles I presume for approximately 95,000 metric tonnes.

The trains length was 7.353km (4.55 miles) long."

Well, that is where I live and I remember the train well, and saw it! And the info here is correct.

I was wondering if anyone can calculate the relativistic effects on the train given a gross mass of 100,000 metric tonnes, and a length of 7.0km (7,0000m), at a speed of 75kmh (that railroad's maximum permitted speed for empty or loaded iron ore trains.)

I am interested in the mass and dimension changes as compared to when the train is at rest. I've tried the calculation myself but get really messed up with the number of final decimal places, and I don't know if I end up talking in milligrams, micrograms etc or micrometres etc.

The effects are minuscule, which is the point of the exercise. To demonstrate the little relativistic effect upon massive (by human standards) objects at everday speeds...

Thanks if you can help,

Democritus