Running a steam loco on British main lines

[Hobbes]

I stumbled across an article in a motoring magazine. British steam enthusiasts built a new locomotive to the Peppercorn A1 design a few years ago. 60163 Tornado was completed in 2009 and now pulls the occasional train - unusually, it does this on the main lines, so you can travel e.g. from London to Newcastle.
However, this meant having to run at high speeds to keep up with other traffic on the line. At 75 mph, the train was becoming an obstacle to other traffic, so a test was organized to see if it could get up to 100 mph.

This is a BBC documentary on that test:
https://www.youtube.com/watch?v=xcBPrfCQMBQ

[PR19_Kit]

The same group are building a reproduction 2-8-2 Mikado as well, based on the LNER P2 design.

[Gondor]

That was good, I really enjoyed watching that 

Gondor

[Steel Penguin]

   thank you for the find Hobbes, a fine watch

[Mossie]

I keep hearing that modern steam engines have the potential to make a comeback, even being small enough to power a car.

We'll see, but it makes me wonder, how quick would a modern steam train be, with an up to date engine and modern materials if an old design can do a ton?

[kitnut617]

Back when steam was about to end in the UK, our physics teacher had his classes out by the main line that ran through Poole everyday. Then one day after the end, he took us for a day trip to the Bluebell line ------

Funny though, every time I look at these old engines, pictures of Thomas the Tank Engine come to mind ---    (and I've got all the original books too)

[Hobbes]

I keep hearing that modern steam engines have the potential to make a comeback, even being small enough to power a car.

We'll see, but it makes me wonder, how quick would a modern steam train be, with an up to date engine and modern materials if an old design can do a ton?

You may have to use a steam turbine instead of reciprocating cylinders to get to really high speeds. As mentioned in the documentary, the motion of the connecting rods creates a vertical force on the track ('hammer') that gets worse the higher your speed.
Steam trains were speed-limited by how fast the crew could shovel coal onto the fire, so you'd have to use a conveyor, or go to an oil/gas-fired boiler.

Ultimately, steam lost to internal combustion due to thermodynamics: a steam engine with boiler is larger than a diesel of the same power, so it has more surface area through which it can lose heat.

The steam-powered land speed record is ~150 mph.