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Bachmann to produce ex LBSC Atlantic H2 Class 4-4-2


Graham_Muz
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Guest spet0114

Beautiful. I hope the con rod isn’t bent the way the GNR Atlantic’s one was. Not that it would put me off getting a couple.

Andy's picture clearly shows the joggle...

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The BR versions looks gorgeous. Lined black seems to suit the class so well. Do we know when they will be hitting shops roughly?

Big James

One would hope the couriers are not as rough as that.

 

 

Rob

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...I hope the con rod isn’t bent the way the GNR Atlantic’s one was...

 As observed above it is, because Bachmann's design is for the 2nd radius capability that is necessary for OO RTR models. (I would have liked an alternative pair of straight rod plus cross head and piston rod assemblies in the box, to be fitted by those with layout curve radii permitting this.) Attempts to straighten the rod, it  didn't like, so I have left it for now with thoughts of looking for a kit replacement in time.

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 As observed above it is, because Bachmann's design is for the 2nd radius capability that is necessary for OO RTR models. (I would have liked an alternative pair of straight rod plus cross head and piston rod assemblies in the box, to be fitted by those with layout curve radii permitting this.) Attempts to straighten the rod, it  didn't like, so I have left it for now with thoughts of looking for a kit replacement in time.

 

That is helpful, thank you. For my part, I didn’t dare assault my GN Atlantics but it is nice to know they’re best left alone. I assume that the reason it’s done is to clear the footsteps, which precludes the usual method of using a spacer to push the big end outwards. Oh the joys of 00! Perhaps it would be less obtrusive If the con rod were to be bent outwards just in front of the big end and inwards just behind the small end but then it might foul the slide bars. They are pretty resourceful at Bachmann and I dare say they settled for the best compromise, thinking that omitting the footsteps would be worse than an S-bend half hidden behind them.

 

It may be necessary but it’s not, in my opinion, an entirely happy compromise.

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Yes, the prettier H2 has landed here which will shortly be in the hands of our Southern guru for review in BRM.

 

 

 

The review is in hand..

 

post-243-0-27441300-1533547468_thumb.jpg

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I hope your Verniers are within calibration ;)

 

It's OK they do not need to be in calibration (although the temperature was pretty much at the 'standard' 20 deg C at the time of the review) for the review to be simply 'she is very pretty' :) but that's more down Marsh and Billinton than Bachmann  to be fair...

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... I assume that the reason it’s done is to clear the footsteps, which precludes the usual method of using a spacer to push the big end outwards. Oh the joys of 00! Perhaps it would be less obtrusive If the con rod were to be bent outwards just in front of the big end and inwards just behind the small end but then it might foul the slide bars. They are pretty resourceful at Bachmann and I dare say they settled for the best compromise, thinking that omitting the footsteps would be worse than an S-bend half hidden behind them.

 

It may be necessary but it’s not, in my opinion, an entirely happy compromise.

 Compromise there has to be for 2nd radius capability to avoid the major risk of the connecting rod fouling on either of the fixed structure of the footstep or the moving leading crankpin.

 

There are two alternative compromises that I would have preferred. Either provide a replacement set of straight rods, or fit straight rods and leave the footsteps as an optional part. (The latter the cheapest method, no incremental parts, and there is precedent there:  leaving footsteps separate to be fitted at owner's discretion is something Bachmann have done on other models.) Let's see what Graham Muspratt feels about it.

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 Compromise there has to be for 2nd radius capability to avoid the major risk of the connecting rod fouling on either of the fixed structure of the footstep or the moving leading crankpin.

 

There are two alternative compromises that I would have preferred. Either provide a replacement set of straight rods, or fit straight rods and leave the footsteps as an optional part. (The latter the cheapest method, no incremental parts, and there is precedent there:  leaving footsteps separate to be fitted at owner's discretion is something Bachmann have done on other models.) Let's see what Graham Muspratt feels about it.

 

Thinking about it, another possibility would be a spacer inside the crosshead or, which I think has been done, an S-bend immediately behind the crosshead. Perhaps that would have led to fouling the coupling rods. As you say, it will be interesting to see what Graham Muspratt thinks, although a response from Bachmann along the lines of, “Shut up. We tried all of those,” would be nice.

 

Perhaps we’ll still be stuck with it on the Small Atlantic. They are working on it, aren’t they?  :D

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 Compromise there has to be for 2nd radius capability to avoid the major risk of the connecting rod fouling on either of the fixed structure of the footstep or the moving leading crankpin.

 

There are two alternative compromises that I would have preferred. Either provide a replacement set of straight rods, or fit straight rods and leave the footsteps as an optional part. (The latter the cheapest method, no incremental parts, and there is precedent there:  leaving footsteps separate to be fitted at owner's discretion is something Bachmann have done on other models.) Let's see what Graham Muspratt feels about it.

 

To be honest, I prefer the footsteps fitted with an S or zigzag in the rods than straight rods with footsteps to be fitted by the customer - but only if they are graced with scale curves. I know it has been done before for front steps, but I feel these are taller and more prominent in the middle than end steps.

 

Spare cranks equates to extra cost on an (I feel) already expensive model which only a dozen people will probably actually use. Clearly a market for after market parts though.

All design is compromise, and I think Bachmann chose the best for this case.

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 Compromise there has to be for 2nd radius capability to avoid the major risk of the connecting rod fouling on either of the fixed structure of the footstep or the moving leading crankpin.

 

The implication is that ALL axles are given significant sideplay ? - surely this shouldn't be necessary on a four-coupled loco even on the tightest of toy train curves !

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The implication is that ALL axles are given significant sideplay ? - surely this shouldn't be necessary on a four-coupled loco even on the tightest of toy train curves !

 I rather think it very necessary, and especially for the notorious set track point with its substitution second radius curve as a sum of two each of straight and sub-2nd radius curved sections. I haven't the set track to test with, but have run the model on a friend's layout with third radius curves, and it hadn't got much more lateral play there. 

 

It isn't in the coupled wheelbase that the problem lies, but with the carrying wheels. The bogie wheels are tight around the cylinders which limits their lateral displacement, such that Bachmann have employed a curved track for the bogie pivot and made quarter cutouts in the cylinder heads at both ends of the cylinders. And the trailing truck is within outside frames constraining its lateral movement. End result is that there needs to be as much sideplay as possible on the driven wheels to make up for restrictions on sideplay of the carrying wheels.

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 I rather think it very necessary, and especially for the notorious set track point with its substitution second radius curve as a sum of two each of straight and sub-2nd radius curved sections. I haven't the set track to test with, but have run the model on a friend's layout with third radius curves, and it hadn't got much more lateral play there. 

 

It isn't in the coupled wheelbase that the problem lies, but with the carrying wheels. The bogie wheels are tight around the cylinders which limits their lateral displacement, such that Bachmann have employed a curved track for the bogie pivot and made quarter cutouts in the cylinder heads at both ends of the cylinders. And the trailing truck is within outside frames constraining its lateral movement. End result is that there needs to be as much sideplay as possible on the driven wheels to make up for restrictions on sideplay of the carrying wheels.

OK ..... I'd better order so more packs of fibre washers for when my malachite green H2 arrives .............. no hurry !

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