5029 on the 9th May

Nunney certainly gave those of us waiting at Hemerdon some fine entertainment this afternoon. I don't know what her minimum speed was, but I'd guess it was single figures. I was half a mile beyond the summit, and could hear the climb very clearly on the westerly wind, but couldn't see. The exhaust beat got slower and slower .... and slower ... I held my breath ... surely she's reached the summit ... and slower! Finally there came a long blast on the whistle and a rapid increase in the exhaust rate, and she burst under the bridge. Thanks goodness the climb wasn't a quarter of a mile longer - I'm not sure she'd have made it, if it was. Or maybe it was a really well-judged piece of theatre by the loco crew? ;-)

The early passage of 5043 was a really nice surprise. Thank goodness for mobile phones and, especially, RTT. In the olden days, I'd have had my camera switched off and pointing in the wrong direction.

 

It was amusing that the departure indicators at Plymouth showed the train as for BTM only; presumably because the steam leg and the diesel leg were operated by different companies with different reporting numbers.

 

Yes Yeti a very good day with 5029 performing well and setting a target which 5043 will be pushed to beat. The dash from Whiteball to Bristol was my best in preservation. We took just 37 minutes and 24 seconds from passing Taunton to stopping at Exeter, 44.74 miles. The 72 at Parsons Street and the fast and bold finish to give an arrival half a minute early in 70 mins 22 seconds from Exeter (75.49 miles on the gps) were all quite superb from driver Vince Henderson, especially as we were 6 late at Tiverton. Nunney is just as good as the Earl on level track but much weaker on the hills. Going down the minimum speeds of 39.6 on Whiteball, 17.8 on Dainton and 16.9 on Rattery were all well below what 5043 has done with the same load. Coming back I didn't think we were going to get up Hemerden as speed had dropped to 7.1 mph before gradient eased from 1 in 42 to 1 in 75 at the top. However a great day all round and much credit to Pathfinder and the engine crews all of whom seemed to enjoy the occasion.

Gricer (CJ) Don

 

Sounds some good times on the flat (ish) sections, the Earl will have to beat it over the banks then what with the 75 limit.

 

Yes I agree. What made that dash special was the unrelenting pushing on at the 75 limit (plus a bit) plus the exceptional finish into BTM.

Don

 

Looks like it was quite a slog on Hemerdon going by this clip on YT:



This great clip of the two Castles passing has also appeared on YT:

 

Looks like some impressive on-board footage from Dave Oldham, as usual. Hope he puts a longer sequence up of it!

 

My video of 5029 storming Flax Bourton yesterday:

 

Anyone know the speed through Yatton ?

 

Climbing to Brewham, close to Nunney!

​

 

It was 77.1 mph

Don

 

Al

In fact the loads were almost the same. Nunney had 8 for 290 tare (5x37t+2x36t+1x33t) making around 315 gross, as it was full. 5043 had 8 for 285.5 tare, or 310 gross.

I think it is more than just the double chimney. As you say some engines are just that much better than others. 35005 as against 35006 eg.

Don

 

Anyone got a spare double chimney and 4 row superheater ?

I must admit I was surprised at just how much advantage the later draughting arrangement seemingly gives.

 

77 mph

 

Yes, 7 or 7.5 mph minimum. I was told the crew said they got the fire wrong at Plymouth but to be fair it was very rushed departure so they were really up against it. The loco pulled the stock in, ran round the train, brake test then right away, hardly ideal.

 

On the departure from Plymouth with 5029, following the delays with the empty stock working and running around etc, the fire was apparently not hot enough and I gather that the boiler pressure fell quite drastically on Hemerdon. However it revived quite rapidly thereafter and I felt that the difference in performance from 5043 thereafter was not really that great.

David

 

The 'good folk of Tyseley' have given it a tweak, which is why it goes the way it does. The same bloke set the valves on both engines and there is no difference in the way that they were done. Whilst it is a fact that some engines did run better than others, there is nothing wrong with Nunney and it was one of OOC's regular performers for many years. There is a certain amount of mythology, mumbo jumbo and superstition in this particular thread as it is a very simple thermodynamic fact that an engine with a double chimney and freer exhaust (less back pressure) and higher superheat (more energy in the steam) is always going to have the edge on a similar engine with a single chimney and lower superheat whether it is on the level or going up hills. The reason that they appear to the uninitiated to be equal on the level is due in this instance to a thing called adherence to speed limits on sections where both types are capable of running at line speed. When the chips are down with heavier loads and higher speeds on the level the high superheat will show its advantage. It should surely be a matter of simple logic that if 5043 is stronger (ie more powerful) on the banks then it will similarly be capable of producing higher outputs on the level, the debate is whether it is called on to do so to match other performances. Yesterday I sat and watched for many miles as 5043 ran consistantly on 17% cut off, just on the main valve and not more than 120psi in the steam chest at 75mph across the Somerset levels. Full regulator would have seen boiler pressure in the steam chest and well over 90 mph. As I said earlier the leveller has nothing to do with the engines, it is all about the speed limits.

Finally in support of Nunney, I am being told by everyone involved with it that it has never been better and what you are seeing is a genuine 2 row Castle in top condition, they always would fly with the right load and the right road, anyone remember the Cheltenham Flyer of the 1930's?

Regards
Bob

 

This assessment of loads appears to be using ancient data for Mark 1 coaches before they were fitted with ETS, Commonwealth bogies and dual brakes all of which added considerably to the tare weight. In our assessment there were 4 mark 1's at 38 tons each 1 at 41 tons, 2 mark 2's at 32 tons each and a REg at 44 tons start and 37 tons final. I make that 301 tons tare, I shall leave you to add the nebulous estimate of how heavy the passengers and the equipment in the support coach were!

Regards
Bob

 

some photos and video from around plymouth of this tour at https://www.youtube.com/user/keyhamtrain/videos?sort=dd&view=0&live_view=500&flow=list and at http://keyhamtrain.weebly.com/