Discussion in 'Steam Traction' started by johnofwessex, Feb 16, 2020.
Very handsome, too.
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Indeed not only is the coal space base higher on the 'scuttle' type bunker, but the overhang starts lower down. 7200 Trust quote 2,700 gallons of water and 5 tons coal, I have seen elsewhere a coal capacity of 4 tons shown for this type, the same as an unmodified 5205.
The only drawing I have is in a 1946 book, it shows 7200 with the original capacities as listed by @Jamessquared.
The 7200 trust do quote coal capacity as beeing 4 tons
However this site quotes 6 tones http://www.greatwestern.org.uk/m_in_282.htm
Wikkipedia quotes 6 ton, although we know inacurate they can be https://en.wikipedia.org/wiki/GWR_7200_Cla
The site run by the group restoring 7202 state the capacity as 6 tons, however the last batch of converesions have less coal capacity of 5 tons , and a little more water capacity of 2,700 gallons as opposed to 2,500 gallons and 6 tons http://www.baldric.plus.com/7202/72xxspec.htm
Photos of 7202 and 7229 show the earlier shape of bunker, made obvious if you look at the line of rivets where the water space is separated from the coal space. Of course so much sheet steel will have needed replacement after 60 years out of service that 7200 may emerge from rebuilding with either type of bunker.
The biggest problem researching anything on the web, is that you don't know what original sources the compiler of a website has used. All too easy to take inaccurate data from one website when compiling another.
This is why history books normally have a list of original sources for factual information.
If in doubt go to the RCTS "The Locomotives of the Great Western Railway". In this case Part 9, Standard Two-Cylinder Classes. Here we have:
I guess my point was - in relation to a rebuild of the 42xx class, by time you have got 6 tons of coal into a bunker, there is not much advantage in having a tender, since the coal-limited range is already such that it is likely more than one crew could burn in a day's shift. (Six tons of coal at 50lb per mile with a half ton unburnt allowance for prudence gives a range of 245 miles, which at 20mph is already 12 hours). So understandable why rebuilt as tank engines rather than go the extra expense of increasing the stock of tenders. The primary advantage of having made them into tender engines would seem to me to have been related to braking capacity, not primarily fuel and water capacity.
Since the bunker/rear tank fitted to 7200 (Diagram A) on arrival at Quainton Rd. is distinctly different to those shown on photos of 7202 (also Diagram A) and 7229 (Diagram B), I believe it must at some stage have been rebuilt with a bunker as fitted to the third batch (Diagram C) locos.
I didn't know that the 72xx had three different bunker types, perhaps some knowledgeable person could explain any visual differences?
If it's any help I've attached photos of 7229 and 7202 at Barry in 1969 and 1970 respectively.
Welcome to GWR standardisation and swapping of (sometimes quite large) components. What is clear is that the GWR decided that the balance between coal and water carried was imperfect and changed it somewhat between the second and third batches. After that one needs to have confirmed dated photographic (or physical!) evidence of any given locomotive at any one time. The myriad detail improvements, changes and reversions made by the GWR to their locomotives makes any attempt to track them a sure way to madness. The RM Web fora have many threads trying to prove one thing or another. Reverting to the RCTS series, the recording of the early swapping of boiler types on, for example, the Stars and Saints is but a taster.
I too am no expert on GWR matters, however this photo from the Buckinghamshire Railway Centre Stockbook website shows the difference.
See Irwell Press 2-8-2 Tank Papers. No date is given, but 7200 and 7201 were rebuilt with the later bunker. Originally the first two batches 7200 -7219 and 7220-7239 both had the same bunker, but there were other detail difference, such as the running boards over the cylinders. However, this difference was altered to the original on some of the second batch 7220-7239.
Well, that's quite fun. So in a class with 3 survivors, all 3 appear to be unique!
I'm not sure how many different configs there are amongst the surviving Castles, but there are two frame designs, and at least three boiler types.
GW standardisation aimed for interchangeable parts at shopping rather than every locomotive identical.
I’m wondering if, once you take into account different boilers, bunkers, sandbox positions, chimneys, cylinder sizes and so on, whether any of the ten surviving Terriers is identical to any of the others.
Well I'm convinced no two surviving Black 5's are alike, especially in the detail.
That was probably true in BR days, too!
so the challenge is now to name a class of at least 3 where the survivors are all identical [grin]
I was going to say the four Wainwright Ps, but I think 753 (the KESR one) has a taller cab.
What about the 80xxx tanks - was there much variation in those?
I've experience of 80072, 80135 & 80136 and I can't think of any real difference. However, when 80135 eventually goes back into service it will have TPWS, GSMR & AWS so it will be somewhat different from the other two.
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