'The Bath and Bristol Christmas Markets'. Thurs. 28 Nov

Now that's a real pain, I was really looking forward to the return over Buriton, the real highlight of the day for me and something I've been wanting to do for a very long time!

However the change allows us to get back at a reasonable time I guess.

 

Now this is a shot in the dark, but www.facebook.com might be a good place to start.

 

Triple headed fives? Well double would have helped on this job with the third as Southall cover. S15, a good engine but it is still two cylinder in poor conditions, would have been interesting to try it. 61994 may well have been a better choice.

 

Thats interesting....returning via READING (just before 9pm). Seems they find a way to get round the steam ban...or could it be because of the block further up the line. Makes sense. I as thinking the 5's would make a decent noise away from Reading station; but they won't have any coaches eh

 

A couple of panniers buffered up to the rear coach maybe?

 

Is this what you call a "Freudian Slip" ?

 

No they don't. Max for a Black 5 is 8 on the NYMR. However, that is overloading them. IMHO. In BR days, they were limited to 5. According to the BR Test Bulletin for 44764, the max recommended load for a Black 5 on 1 in 60 is 282 tons to maintain a minimum speed of 20 mph. In my book, that works out at about 7 coaches.

 

A couple of them - one by Bryan, and another by me!



Steven

 

In my visits to the NYMR over the years 7 had become the norm with the spare coach from Pickering added sometimes in the peak. However since I moved away from York I don't get there as often so apologies to readers if 8 is now the norm.

 

John, you've answered your own question - if 7 is the norm but a spare is sometimes added, then the max certainly can't be 7!

The gradient is king. For example, a Black 5 is about 125 tons including tender. Add 11 coaches - say 400 tons. That gives 525 tons gross weight, which on a 1:60 gives a gravitational pull back down the hill of 19,600lbs, against an available TE of about 25,500lbs. Add in the rolling resistance and that's precious little margin for error, even assuming that railhead conditions are good enough to enable the loco to develop close to its theoretical TE actually on the rail.

The gravitational pull changes very quickly with gradient once the gradient gets steeper than about 1:100. For example, recently on the Bluebell, the Black 5 took 11 + Braunton on the 1 in 75 up to Three Arch Bridge (see videos previously posted here). Braunton wasn't doing any work, so assume a load of about 140 tons extra - say 665 tons. On a 1 in 75, that gives a gravitational resistance that is very similar - 19,800lbs. On that occasion, the loco managed - just - but the West Country started doing some work north of HK. The Black 5 certainly wouldn't have made it alone up to the tunnel with that load.

There's a massive difference between 1:60 and even 1:75 - for the same level of effort on the 1:60, you can take about four more coaches on the 1:75. Flatten out further to a max of, say, 1:100 and the sheer gradient is no longer going to be the limiting factor on the load - acceleration from stops, platform length, distance between water stops is going to be more of an issue. But once when you get to steeper than about 1:100, the safe number of carriages is going to start going down very quickly. As someone mentioned earlier - a Black 5 might be good, but you can't beat the laws of physics...

Tom

 

I admit it's like comparing chalk with cheese but, the Crompton's 45,000 lbs tractive effort would have been fairly useful on Thursday morning!

 

An M7 on the back probably would have been sufficient...

Tom

 

Swanage is only 18 miles from Poole...... 30053 is running this weekend!

 

And Tom, there was one there waiting.





Oh, it was just a small matter of more than 51 years ago. When I took that photo. The crew might have got fed up and gone to the pub.




.

 

Extra 19,000 lbs????

 

Why not? The M7 adds about 2,200 lbs extra gravitational drag on that gradient, but 19,000 lbs extra force. The margin for error gets a lot more in your favour!

Tom

 

Contributions for TPWS, OTMR, GSMR & certification gratefully received by DLL!

 

Mere technicalities … ;-)

Tom

 

I'll settle for a couple of BSWs myself.