Whilst sitting on Dawlish platform this evening i was looking down the track seeing how tight the bends seem which got me thinking what would these radii work out to in N is there any way of calculating it from google maps?


Dave

It would be quite easy if you paid attention when they taught you geometry in class   

I will try and do an example to show you as  picture will show you more clearly than a load of text 

You'll find the answer is big.  Even what we consider a generous curve in N would probably be limited to about 10mph on the prototype! 

Just to show that there are (or was in this case) some really sharp curves that could easily match the smaller radius's... This is the entrance to Fry's in Keynsham (later known as Cadburys).

Taking a very simplistic approach and answering the opposite question to the one you have asked a Peco 9" curve multiplied by 148 = 1332" which is 111'. 4th radius has a radius of 161.5' in the 12"/foot world. Hope that helps but probably not 

Quote from: 4x2 on April 13, 2012, 12:04:48 AM
Just to show that there are (or was in this case) some really sharp curves that could easily match the smaller radius's... This is the entrance to Fry's in Keynsham (later known as Cadburys).

And even later known as Kraft (we're moving your jobs to Poland) Foods. RIP the Somerdale factory.

Quote from: Trainfish on April 13, 2012, 12:16:47 AM

Quote from: 4x2 on April 13, 2012, 12:04:48 AM
Just to show that there are (or was in this case) some really sharp curves that could easily match the smaller radius's... This is the entrance to Fry's in Keynsham (later known as Cadburys).

And even later known as Kraft (we're moving your jobs to Poland) Foods. RIP the Somerdale factory.

Tell me about it... If the wind blowed in the right direction, the wonderful smell of chocolate would drift through the house (I only live 2 miles away), but no more... That factory was the pride of Keynsham, now destined to be another housing estate (who's gonna a buy a house in curly wirly close or wispa ave loads more - but all naughty ).

Would make a great industrial layout though, the idea of the works shunter trundling through those big iron gates has always interested me... one day i'll have a go !

Can't be that sharp - it's got an 08 going round it and they were limited to about 3.5 chains radius. 3.5 chains is 231 feet or in 2mm thats 460mm radius (18" radius)

Some docksides and industrial sites went down to 100ft radius or so: 200mm radius (close to a Peco R1) but other than very small wheelbase shunters and carefully chosen wagon types nothing would traverse them. The one location I know of that had 100ft radius curves and needed serious power due to the 1 in 20 gradient out of the works onto the GWR had a Beyer Garratt with two four wheel bogies.

Early BR diesel days saw various very small shunters designed for this kind of work but in time they all got scrapped as such sharp docksides went away.