The Railway Children

[Brian Gaff]

Is this the original film, if so it was a long time ago and at that time I do not think it was expected to be such a major hit film, so budgets were no doubt squeezed. Brian

[NY]

This was the 1970 film with Jenny Agutter, Bernard Cribbins and Sally Thomsett, and directed by Lionel Jeffries. I wonder how much of a hit and a cult film it was expected to be.

There are a few little clunky bits with effects: in the famous scene of Jenny and Sally waving red flags (*not* red knickers - that's the stuff of fantasy!) at the approaching train, there is a shot of the train working hard, with clouds of steam billowing from the funnel, followed after a cutaway shot of about a second, by a shot of it "approaching" with no visible smoke/steam at all. Even allowing for the driver shutting the regulator and putting the engine into reverse "gear" (reversing the valve/piston timing), this is implausible. It is probable that the second shot was filmed in reverse (to avoid the train having to stop accurately where Jenny was standing), maybe even with the train hauled by an an unseen loco at the other end.

I presume for "reverse gear" to have maximum effect, steam pressure has to be maintained (ie regulator open) to provide pressure to act *against* the pistons to help slow down the train.

[soup]

That's what a life of drink, drugs and smoking does to you.

[soup]

Perchance counterintuitive but no.

Action such as you describe would make the wheels slip on the rails, and as the coefficient of sliding friction is lower than the coefficient of static friction ...(witness, 'once it's going it is easier to move') . Much better to slow the wheels by braking than trying to throw everything into reverse.

Doesn't mean train drivers(engineers) never panic and throw everything into reverse, cue old film of trains with their wheels spinning whilst trying to stop.

C.F. ABS in cars lets the wheels keep revolving (stops skidding and slows the contraption faster.

[Bob Eager]

Red petticoats.

[NY]

I was assuming that the reverse valve timing provided additional loco wheel braking, to supplement the normal service brakes, but was not so great that it locked the wheels, so still used static rather than sliding friction. As with any vehicle, the skill is in manually controlling the braking (by tyre brakes and reverse valve timing) so as to get the wheels almost but not quite to the point of locking, in the same way that ABS does automatically.

On modern trains, I presume there is an ABS/wheelspin system which does all this automatically once the driver hits the "emergency braking" button, braking each axle almost to the point of slipping, without any fine-tuning of the braking level by the driver.

[Geo]

=============== Condition: Used

?very good? ===============

<snigger>

[Harry Bloomfield]

Well Sallies 'budgets' were reputed to have needed to be squeezed :-)

[Binkie Huckaback ...]

and driving a merc convertible ,,,,,,

[Binkie Huckaback ...]

that is what I said ...

[Cursitor Doom]

That's nothing. IIRC there's a shot of this steam train rollin' along and some 'A' road in the background with a string of 1960s cars and trucks on it.

[Harry Bloomfield]

Well then, stop morphing your name so your posts don't become plonked.

[Jim K..]

(It was a film for children...)