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72xx loco

2528 Views 9 Replies 3 Participants Last post by  kristopher1805
Hi Just received a new loco well it's never been run but a few years old . A 28xx so not having a running layout at the moment i set up a test track on the floor not ideal i know but i needed to check it was working. So after some oil in the right places i ran it for a while forwards backwards turned it round and run it forwards and backwards again all good. While i had the track set up i decided to run a couple of loco's that i did not run last time(Christmas). One of which is a 72xx as i recalled it never went very fast in fact it must be the slowest running loco i have. I had to turn the controller quite far before it will even budge and on full power is about half as fast as the 28xx . I know this is a freight engine so will not be very fast, any way i'm wondering if the model is particularly geared that way to assimilate the prototype . To further test this i decided to put it front of some wagons thirteen war wells five Oxford and eight Hattons /Bachmann. and a GWR Toad. The Oxford versions are very light in weight where as the Hattons versions are quite weighty . Seeing as i have not had these run before i went the whole hog and loaded the three Oxford and ten of the twelve Airfix Sherman tanks i have on the wagons. As a side the Oxford Shermans have diecast hulls so are heavier than the plastic Airfix models.

The results were as :-this train made no difference to the 72xx no slipping and seemed to run not much slower than without pulling the train. The 28xx however applying to much power slipped but when applying power slowly pulled away ok though if you put full power would slip again so half power only. I also tried three other loco's 38xx , better than the 28xx , 47xx Heljan (very heavy model) pulled no problem at all excellent and a Bachmann 57xx , slipped badly to start but once going pulled ok. Has any one got any thoughts as to why this loco' is slow i have heard of complaints about this loco but not about its running. I am not bothered about the speed just curious that it should be this way .Jim
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OK I have all these locos 28xx 38xx 72xx 30xx O4 (lots of) along with O1(2), 8F(4), O2/3 and O2/4, 47xx and Q6 and bed iron (O7, austerity 4) and G2A(3)

So of these the 72xx is a bit slow but pulls fine I have sometimes used it as a recovery loco/thunderbird but feel a 42/52 would be better as pony trucks are easier to derail.

There is no doubt that the O2 will pull but it dislikes corners and anything less than absolutely flat track had issues with the front pony truck wheels

The 47xx is better on the track than the O2 it will take slightly tighter curves and I have not had to change the pony truck wheels but it does have some grunt, generally I use it where I have R5, R6 type radius curves anyway but I generally like these locos. As a kid I know I saw these on holiday specials but I never remember them.

The austerity is an excellent bit of kit, my father had some but as they were worn out pre dcc fitted I sold them off in favour of 4 new ones but they are really good.

The 28 and 38 seem to be a bit fragile I do not use them so much.

Slowest of the slow is the Q6 it relies on gearing and seems to have a smaller motor but it slowly moves around the layout and to be found on presflow Maltese freights. These are Wrenn wagons and there is nothing lightweight about 1 dozen of those plus a Wrenn. van but it has a very realistic speed and an elegance all its own.

O1 is a honey - excellent all rounder

8F getting long in the tooth as a model but still a good 'un

30xx and O4, (or 8k, ROD if you prefer) is also an excellent effort always have one or two on the roster, worth the investment.

So I think the 72xx has been a good loco and better than 28/38xx types as a running loco. Pick of the bunch the O1 though.
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Q6 hauling Wrenn. 16 ton coal empties

4709 hauling a van train

You always forget one, I have 5 of these and a kit built one as well, as for the Bachmann 7F this is a very good model - find an excuse to buy one!
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it seems that many folk do not think that S&D locos wandered north of Bath, there had been a Midland shed here that became a workshop for the wooden green park loco depot and indeed the allocation worked that far north.

In the 1920's there was a competition to find the next freight loco for the LMS with trials on the Midland main line and this turned out to be a fight between the Midland who put up the SDJR 7F which the Midland felt was a ready winner and the LNWR G2A, despite rampant favouritism for the 7F the G2A turned out to be the better loco and so the Midland men at Derby did what they usually did, built a Midland version of the G2A which was called the G3 and became the unloved 7F or Austin Seven, or Roller Skate, it did include some improvements over the G2A if nothing else to lay the cylinders down flat, give an easier layout of valve gear and to lose the 'arseburner' name tag but in the end this loco was pretty much unloved such that many had short lives but it was probably one of the better efforts for an 0-8-0 and was needed when it came in to service.

As to the 7F no more were built, Clayton did a decent job originally but better work on the valve gear would have done the job but Derby was confused at this time, the young designers went on to do the 2-6-4tank and what a success that was whilst the old stagers produced the dismal 2-6-2 tank in fact the 2-6-4 valve set up was used exactly for the North British built Royal Scots.

Me - well I would have gone to an easier solution and built a 2-8-0 version of the Hughes 'crab' which was ultra popular in the traffic and running departments. I would point out here that after some study it seems that the ratio between firebox grate area and heating surface was critical, bad here the GCR later 4-6-0's with a ratio around 100:1 whilst the crab was nearer 50:1 (not checked - from memory)
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