Bachmann Deltic Review.

...except for the gap between the bottom of the windscreen and the top of the bonnet.

I am using photos and drawings from BR Mainline Diesels. In it there are close ups of the No1 ends of both D1 and 44008. According to those photos the cabside grilles on 44008 do not curve at all and those on D1 are not nearly as wide as on the Bachmann model. According to both drawings and photos the dividing line in the grilles is not dead centre when viewed from the side. In fact, the front part of the grilles and rest of the nose combined are only about as wide as the rear part of the grilles. I suspect somebody from Bachmann tape measured round the curve on D1 then translated that to a flat drawing? The discrepency is exaggerated on the model of 44008 due to the dividing line between the blue body and yellow ends being too far forward.

I am not a fan of either the 44 or modern image so it doesn't bother me as much as it does some others.

kim

It isn't the overall length of the nose which is the problem. It is the width of the cabside grilles relative to the nose. They extend too far forward and prevent half the depth of nose ends from being painted yellow.

(kim)

"Kim Pateman" wrote

Well that's fuffed your credibility. The drawing of the 44 in said book omits the main generator exhaust vent (on a par with missing the chimney from a steam loco) and guess what's missing from the Bachmann 44?

Seems that the Marsden/Fenn volume is full of inaccuracies, so you cannot use that with any degree of certainty that the faults you are pointing out are not faults with the drawings themselves.

John.

That photo clearly shows the curve in the bars on the front half of the grill, try a magnifying glass.

Indeed and the grills on the Bachmann model are not divided in the middle either, they are just like the drawings.

Rear part of grill, Model: 4.8mm, drawing: 5.3mm Front part of grill, Model: 3.8mm, drawing: 3.6mm Dividing bar of grill to front of nose, Model: 7.3mm, drawing: 7.3mm Door edge to dividing bar of grill, Model:19.3mm, drawing:18.5mm

Make of that what you will, I would give little credence to the drawings in Marsden and Fenn in general but they seem pretty close to the photos in this case.

If there is a significant discrepancy on the model its the window area, as you say the space between bonnet top and window bottom is excessive, also the drawing show the centre window further forward at the bottom with significant angles to the side windows, the model is flatter. I have yet to find a photo taken from an angle where this can be seen so its an open question to me.

I haven't got a blue one to look at but there's not much yellow round the corners on the photos, the 44/45/46 always look snub nosed, conpared to the much more handsome 37/40 noses.

Keith

Make friends in the hobby. Visit Garratt photos for the big steam lovers.

Have you tried this? I spent 2 Saturdays a month over a period of 18 months going over Tulyar. As I mentioned elsewhere in the thread, all four corners differ in radius, so which to choose as correct? In this instance only No1 end driver's side was a true arc, so I chose that. The rake of the nose panel at the centreline was different at each end, so which was right? (It was of the order of 3/8" difference, from memory.) Similarly, surveying the nose top slope was tricky. I got one figure internally measuring from the deck plate, and then went and bought a laser level and shone that along the roof to take offsets and got a slightly different reading. That could be down to the underframe camber I suppose, but again, which to choose?

Then there's the bits which have disappeared for all time, like water pickup and bodyside filler, the sand fillers, and the cab quarterlights.

I asked them. A fairly senior figure, whose name appears as co-author of a book about a BR Standard, told me they had none for the Class 55, and not for want of his personal efforts, in trying to track some down as supporting material for the example they have in the National Collection. I followed up with an enquiry as to whether other EE designs of interest to me were better covered, and he said he "had no reason to believe" they had any technical data in the EE collection.

York is too far for me to go on a speculative visit to prove whether this is true or not. Do we know anyone living nearer who could pop in and find out? ;)

Cheers, Francis K.

I share these hopes. Unfortunately, I came across a print of the body panelling, reproduced from microfilm, I suspect. (It had a RX 'stamp' in the corner.) It was almost illegible. The lines were evaporating and dimension numbers were coalescing into blobs, or disapearing into dark clouds. Clearly the original master was deteriorating when the microfilming was done, proabably to try and stop the rot, but may not have been done with the care in exposure required to maximise the capture of data. If the master was then disposed of, the data is possibly lost forever.

I recently chatted to someone who was a draughtsman at Derby, and got told off for producing drawings unsuitable for microfilming, judged by the resulting prints. He then produced his originals, which were crisply drawn in ink. It turned out that low paid contract staff had done the microfilming and had changed a bulb without re-calibrating the camera.

Cheers, Francis K.

I'm not sure they have one! If you chat to one of the bosses at an exhibition, you may get the impression that the drawings are done in China. Certainly, when I showed interest in the problem of moulding the Deltic tumblehome without needing excessive wall thickness higher up, the reply was that they hadn't looked.

Cheers, Francis K.

=>John Turner wrote: =>

=>> "fladda" wrote =>> =>> > Part of the problem with producing good ready to run models in the UK =>> > appears to be the relative scaresity of *accurate* drawings. =>> =>> Good grief, I despair, why when there are examples of the prototype in =>> preservation is *scarcity of accurate drawings* an issue? =>> =>> All the model makers have got to do is go measure up one of the preserved =>> examples, and seek out the manufacturers' works drawings and compare these =>> with their own findings. =>

=>

=>Have you tried this? I spent 2 Saturdays a month over a period =>of 18 months going over Tulyar.

Now translate that into salaried time.... It's astonishing to me what peolple will think is "just a simple job of measuring." Merely comparing design drawings to works drawinsg can take hours. And comparing either to as-built will take days, as you've mentioned. For that matter, a shop crew may spend a great deal of time trying to figure otu which drawings they should rely one when faced with repair of a much modified engine....

Also, people put far too much trust in "preserved locos." These have all been "restored", which means someone had to interpret whatever data were available to bring the engine to some specified condition, about which there will be limited information. For example, what do you do when it's known that some locos in a batch received certain mods and others didn't, but there's an incomplete paper trail to determine which did and didn't, and your loco happens not to have been recorded on film at the crucial time? While major dimensions will be reliable, details and their placement will be matter of opinion. And it's amazing how much information about paint has gone missing. Not to mention the fact that often the "restored" loco is a melange of parts from all over the place... Etc.

IOW, all information about the past is unreliable is some respects; and as often as not we just don't know where reliability ends.

Already in this thread people have pointed out errors in various published sources. The authors obviously didn't have the vast resources available to the critics. :-) Or else the critics have been sitting on valuable data instead of sharing it by donating it to some preservation society or museum. Most likely, though, the authors did the best they could interpreting conflicting data and trying to fill gaps with reasonable guesses. AFAIK, all such published books are labours of love - even the ones issued under the imprint of a museum. If the crirtcis have reliable infoprmation, good, let them publish it as a corrections or addtions to the book; but don't criticise an author for not having data that only you have, or for intepreting ambiguities as best they could.

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

If it's not controllable within a couple of percent, then how do they ever hope to get the parts to assemble correctly?

This should be Bachmann's (and Hornby's) problem, not ours. The drawings done in China can be sent electronically in minutes back to the UK for verification and approval.

Cheers, Francis K.

OK. Here goes.

From a datum point on the nose framing, on the centreline, just above the buffer beam:

To bufferbeam: 8" Horiz To rear of cab door: 13' 5" Horiz To point of windsceen vee: 5' 5" Horiz, 6' 5" Vert To base of nose 'dome': 3 3/4" Horiz, 4' 8" Vert To line extended from nose top slope [1]: 0" Horiz, 6' 2" Vert Point of windscreen vee to front rail of bonnet hatch: 3' 7" On slope

[1] Slightly different interpretation to a previous note from me.

=>Wolf Kirchmeir wrote: =>

=>

=>> Major dimensions and body shape should be spot on IMO, major detail likewise, =>> but deviation by a couple percent is OK, considering the not entirely =>> controllable factors of shrinkage etc. =>

=>If it's not controllable within a couple of percent, then how =>do they ever hope to get the parts to assemble correctly?

What's 1% of 1mm?

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

I heard as much from a Bachmann representative present with their pre-production model at the DPS depot opening a few months ago. In fact, he'd found the successors to the BR RTC to be much more reasonable than the NRM, even though they're now commercially minded.

Would this high charge apply to 'cottage industry' scale producers too?

Cheers, Francis K.

I have. It's scary. I assumed a serious manufacturer might invest in some data capture technology to speed up the survey process.

Oh yes. And some of the preservation movement takes a 'pragmatic' rather than historical/academic view of the details of livery. As long as it helps to stop it rusting away, and all that. I've been looking at BR (1957+) totems on preserved locos. They're all symmetrical. So are those for models by Fox Transfers. I have a pair of drawings, ex BR/OPC scheme, date stamped 1963, which clearly shows the bars either side of the circle are unequal lengths. I think the preserved prototype is being infected by some modelling misconceptions. An intersting exception was D345, according to a detail photo posted in alt.binaries.pictures.rail a year or so ago. I must ask them where they sourced their emblems from.

I've been pondering the best way of communicating assumptions and guesses at the time of publication. Would a publisher be happy to have a load of admissions of this nature in print?

Cheers, Francis K.

"Wolf Kirchmeir" <

Very small?

-- Happy Holidays Roger T.

of the Great Eastern Railway

Roughly 3.7735849056603773584905660377358e-4 of an inch or thereabouts. Or in railway terms about 1/8th of a smidgeon.

"Chris Wilson" <

1/8th of a smidgen? Now THAT I understand.

-- Happy Holidays Roger T.

of the Great Eastern Railway

"Francis Knight" wrote

OK, let's do some sums. Two days a month over 18 months equals 36 days. Let's say you spent six hours on each of those Saturdays - that equates to

216 hours and let's cost that at GBP20.00 per hour which gives a total cost of GBP4320.00 - or with expenses call it GBP5K.

Now let's assume that the total research and tooling cost for the Deltic was GBP100K - then in my opinion that 5K is relatively small beer, and indeed money well spent if the end result is a more accurate model.

Now this may not in itself result in a fault-free model, but coupled with looking at established drawings, and checking out anomolies thereon, some fundamental points may be clarified.

Would for instance the main exhaust vent on the 44 have been omitted if the manufacture had closely looked at one of the preserved examples?

John.

Not a lot?

I've managed to measure the model nose 'drop' more accurately now, and arrived at a figure of 0.99mm both ends. This corresponds closely with

1.00mm derived from Francis' measurement. Point of screen vee to front edge of bonnet hatch is 14.4mm, versus 14.33mm derived from the 'prototype' measurement taken. I'm surprised by this since the model's nose looks a tad short. Presumably there may be some variation on the full sized loco's noses, especially if they have been bashed in and straightened out!

I'll check up on the other nose dimensions in due course.

I've put a collage online to compare the nose/cab area with 2 photos of the real thing (55019 and D9000). Both were taken at a level just below the top of the nose, but at different positions along the horizontal plane showing how this changes the apparent shape even over a short distance between view-points. The photo on the left is more repsresentative and one can see a slight nose angle error:

I rotated each photo until the cab doors were vertical. The photo of the model was taken from a larger scale distance so the perspective is still not an exact match. The slope of the quarter-light window is a more noticeable error.

Ian