Hod Carrier

[OcTRAINber MOC] LMS Articulated Railcar (1938)

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On 9/9/2022 at 2:35 PM, Darkkostas25 said:

Yeah, a lot of people underestimate the power of Teknik parts in their builds. It can provide a great solution for lots of builds.

I agree, but sometimes it can be difficult to integrate Technic parts with System bricks because it has a slightly different geometry.

On 9/9/2022 at 2:35 PM, Darkkostas25 said:

The more I look at it the more I see where also it can be used. You have done a great base for Zephir and flying hamburger or maybe for something else (I mean rolling stock of the USA and Europe).
Astonishing work! 

Thank you. That's very kind of you to say. We have seen Zephyrs and other round fronted trains down the months and years, some using different techniques. I think that what I've done is just a different approach to the same problem.

On 9/10/2022 at 4:41 PM, Paperinik77pk said:

Great DMU - the work on the "nose" is impressive - the more I look at it, the more I am amazed on how you did it!!! *huh*

Also the sides, well, are not easy at all to achieve - and again , you succeded in reproducing that shape. Great job as always!  :wub: 

Can't wait to see the "transformed" version! :thumbup:

Ciao!

Davide

Grazie, Davide. That's very high praise indeed. I'm pleased that you like what I've revealed so far and hope that the finished product meets your anticipation.

20 hours ago, zephyr1934 said:

Technic bricks pinned together can still have a lot of sag. If you want stiffness, a sandwich of three plates tall will be stiffer. That is simply a "just in case" suggestion if the technic gives you problems.

 

13 hours ago, Toastie said:

That is certainly true! But when you want to take advantage of the Technic bricks "hole functionality" (other than connecting them), then bracing them (two Technic beams separated by two plates + bracing part, e.g. diverse Technic 0.5 beams or even full beams) makes the "structure" vertically really stiff. At least this is what I have experienced.

I have to confess that I've not experienced problems with pinned Technic bricks sagging. The trick that I've employed is, as with all LEGO joints, a generous parts overlap and plenty of friction pins. If anything, I'm more suspicious of stacked plates as I have found that once you get out beyond a certain length the construction takes on a banana shape that means it needs securing at both ends and in the middle too. My experience is that bricks, Technic or otherwise, are far more resistant to this distortion and, because of the rigid sides, less prone to vertical flexing. I appreciate that joining bricks together introduces points of weakness where flex can creep in, which is why I try to design in such a way as to mitigate against this. Looking back at previous builds I have found that a lot of them have exceptionally strong structures. I really do build them like tanks. :iamded_lol:

In this instance, the spine is built up with plates, tiles and interior detailing and will have the various other sub-assemblies attached, either directly or indirectly, which will be stiff in other axes and add to the rigidity of the whole. I am not anticipating too many issues, but overall rigidity is in the back of my mind and I am prepared to perhaps make alterations as the build progresses to address any problems that may arise.

20 hours ago, zephyr1934 said:

How did you articulate the cars? It would be interesting to see your solution because getting sufficient clearance on curves can be tricky.

I have something that works quite well as "table scraps" but will need to be built and tested before I say anything much more about it. However, if it works as I hope it will, I should be able to run this model on tight curves (perhaps even R40s) even with the car spacing you see in the renders above.

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While I wait for the Bricklink orders to come rolling in, it's perhaps a good time to turn our attention to what happened next for the LMS articulated railcar. When we left the story last, the railcar had been stored out of use following the outbreak of war in 1939. So, what happened next?

With the end of hostilities in 1945, the railways were in a poor state and the railway companies not in any position to restart any experimental schemes that had been underway prior to the war. The main priority was rebuilding and re-establishing a peacetime economy. Nationalisation and the creation of British Railways followed soon after in order to deal with the backlog of maintenance and to make good bomb damage to the infrastructure and losses in locomotives and rolling stock.

It would seem that the newly nationalised railway had no interest in developing the LMS railcar any further, but it still remained as an asset. It was decided to convert the railcar for use as an overhead line maintenance train on the Manchester South Junction & Altrincham route, which had been electrified before the war. The advantage of using a diesel railcar rather than a steam hauled maintenance train for this purpose should be obvious.

There is not much information regarding the conversion of the railcar, and it seems to have attracted little to no attention during this phase of it's existence. The only source material seems to be an article in a 1949 edition of Railways journal, which handily survives online thanks to the LMS Carriage Association who reproduced it in an edition of their online newsletter. This contains a brief description and the only three photos of the maintenance train that I have been able to find.

The trouble with this lack of information is that it makes it hard to know how to design and build a model of it. So far, this is what I've come up with.

52366290673_b9074123ee.jpg

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It looks like a totally different train, doesn't it? However, I have retained the body profile of the original as much as possible to show the family lineage.

At the moment this is very much v1.0 with a lot that still needs to be addressed. As you can probably tell, I have so far simply designed one car and copied and pasted it across to make a second to give an impression of how the railcar should look.

If you compare the renders with the photos in the article, you can see that there's going to be quite a lot I'm going to have to guess, including the colour. I've opted for dark green because that was the colour of passenger railcars (DMUs), but also because the photos show that it had a lined livery rather than being painted a plain colour. What I cannot see is the layout of the equipment below the floor or the layout of windows and doors on the second vehicle. It appears that there is a toilet because there is a window that has been whited-out, but apart from that it's hard to see anything else.

One aspect of the design which has already caused some headaches is the roof. Having a working platform on the roof means that there is a safety lip at the edges which I obviously wanted to retain, but I still needed some way of attaching the cheese slopes at the roof edges. The result of the need to use brackets meant that the roof was narrowed by half a plate at each side from 5 studs, already an awkward number, down to 4 and a bit, so I couldn't just lay tiles and call it done. It was going to need a different solution.

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It took a bit of mental gymnastics but I finally arrived at a solution that I am satisfied with. Underneath it's a riot of brackets holding everything together. Apart from this, the rest of the structure is fairly conventional. Because this version of the railcar did not have the streamlined paneling, the construction of the model is very different from the original version and uses some more conventional techniques.

The lack of source information is a real issue for me in designing this version of the railcar. The photographs accompanying the Railways article are of poor quality and a very long way from comprehensive. I only have a single grainy three-quarter image of one side of the railcar and no idea of what the other side looks like. Even pre-war photos of the railcar without it's lower paneling give little idea of the layout and appearance of the underfloor equipment. The only option that I have left to me to try and gain any better impression is to take a trip up to London to visit the British Library to see an original copy of the article and hope that the photos are of better quality than they appear in the LMS Carriage Association reproduction.

To complete the story of the LMS articulated railcar, it would seem that the railcar saw little use as a maintenance train and was moved from depot to depot before finally ending up at Longsight in Manchester. Here it fell into a state of dereliction and was finally disposed of in 1967.

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On 9/12/2022 at 6:53 AM, Hod Carrier said:

I have something that works quite well as "table scraps" but will need to be built and tested before I say anything much more about it. However, if it works as I hope it will, I should be able to run this model on tight curves (perhaps even R40s) even with the car spacing you see in the renders above.

Can't wait to see what tricks you produce

 

On 9/18/2022 at 8:45 AM, Hod Carrier said:

52366063546_8f418d08ea.jpg

It took a bit of mental gymnastics but I finally arrived at a solution that I am satisfied with.

That makes my head hurt. But aside from the brain-strain it is looking great

Your topic has got my interest, I assume you've seen the following links,

Middle of this notes a lot of references to what appears to be a trade journal, "The Engineer, 1 April 1938." (but I bet they reproduced all of the relevant photos on the webpage). This Wikipedia page discusses the interior of the line car

 

 

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7 hours ago, zephyr1934 said:

Can't wait to see what tricks you produce

I hope I haven't over-promised and end up under-delivering. :look:  Watch this space for developments.

7 hours ago, zephyr1934 said:

That makes my head hurt. But aside from the brain-strain it is looking great

Thank you. I'm glad I could come up with something that works, but it is a fairly bulky solution that is causing some new headaches in other areas, but I'll find a way to work around those.

7 hours ago, zephyr1934 said:

Your topic has got my interest, I assume you've seen the following links,

Middle of this notes a lot of references to what appears to be a trade journal, "The Engineer, 1 April 1938." (but I bet they reproduced all of the relevant photos on the webpage). This Wikipedia page discusses the interior of the line car

I have. :grin:

The Disused Stations page is probably the best overall summary of the development of the railcar, and a bit of a departure for a site that normally focuses on stations, infrastructure and services. Of course, as this specific page relates to the history of Cambridge station and it's railway connections, it focuses on the period when the railcar operated within the area and shows photos of it there rather than elsewhere. (As an aside, Disused Stations is a brilliant website for browsing if you're at all interested in British Railway history as it documents not only closed stations and lines, but it captures former methods of working and services too. It's worth an evening just for the photos alone.)

The entry on Wikipedia takes the information largely from the Railways article of December 1949 that I linked to in my previous post. As far as I can ascertain, this is the only source of information relating to the railcar in it's later guise as a maintenance vehicle.

Luckily for me, the British Library in London hold copies of both Railways and The Engineer, as well as a few other promising titles, that may yield some more detailed information, and I will be heading up there in a couple of days to try and see them. You may well be right about the use of images from The Engineer article, but without seeing it for myself I wouldn't know for sure. I'm hoping that maybe there will be some other visuals (diagrams, drawings, etc) or at least a reasonable description that might help with the build, but I'd be happy if I only find out that I've already seen all there is to see and there's nothing more. Either way, I can get on with the design by following the information I discover or by going my own way and making something up that at least looks reasonably convincing.

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This is the point where I have to come clean and make a small admission. Prior to starting my OcTRAINber entry I had already spent several months working on another articulated train which is now an advanced work-in-progress. Therefore, a lot of the engineering decisions that I have made for that design can simply be copied across to this one giving me time and capacity to devote to other aspects of the design. Admittedly this other project has not been built yet so the LMS Railcar would act as a prototype to test these ideas. Therefore, what follows is something that I've been sitting on quietly for several months rather than the fruit of the past few weeks.

I had been applying my mind to the question of whether or not it might be possible to come up with a genuine LEGO solution for close coupling. To that end, I spent some time tinkering with some Technic elements to see what might be possible, during which I came up with the following arrangement of parts.

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As you can see, this arrangement permits a sort of floating pivot point along what is almost a straight line. The advantage of this is that it would permit two vehicles to be close coupled on straights but gives sufficient clearance for curves and movement of the vehicles relative to each other.

The original idea had been that this would be used for bogie vehicles. The mechanism would be mounted within the body of the vehicle with a straight bar coupler to join the vehicles together rather than a magnet as normal. Because each vehicle would centre correctly due to the bogies making reference to the track, this should not need anything additional for the geometry to work. At present, I have not had any time to build or test this idea.

The problem with articulated vehicles is that this would not work correctly since it relies on each car making it's own reference with the track. Because articulated vehicles share a single bogie, the only way to achieve this would be to have two pivot points, one per car, as quite a few builders decide to do. The downside of this is that it doesn't result in accurate movement of the train through curves and points/switches, which is something that I wanted to avoid. The majority of articulated vehicles use a single shared pivot point over the bogie which means that the cars can articulate independently of bogie and the bogie rotate independently of the cars. So how am I going to make the cars centre when there is nothing to apply the relevant force?

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Simple. I use a rubber band which pulls the end of the mechanism back towards the chassis centreline.

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Two cars coupled. The bogie is pivoting around a 5L Technic beam, which is conveniently hard to see because it's black, which forms the bar coupling between the cars. You can see the offset in the mechanism due to the articulation between the cars. Articulation and bogie rotation work independently as intended. A quick spin around a test track shows that it's working just as I hoped it would, with everything running nice and smooth. It even copes well with LEGO's horrible R40 curves. I'm just hoping that adding weight to the cars as they are built up does not negatively impact on this.

On the downside, the use of rubber bands does now mean that this is a mechanism that will require servicing from time to time as the bands perish and need replacement. The other aspect of this which I think is a bit of a shame is that this is the sort of thing that's quite clever but, because it works well, is likely to go almost totally unnoticed when the railcar is finished.

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40 minutes ago, Hod Carrier said:

On the downside, the use of rubber bands does now mean that this is a mechanism that will require servicing from time to time as the bands perish and need replacement.

Brilliant - as expected - solution. What else ...

With regard to the rubber bands: The LEGO varieties (red/blue/yellow/white) "live" much, much longer than the household-type bands. Do you see any chance to use e.g. the red one? It will expand the service interval significantly. I experienced that on the "Technic" Star Wars series droids. They came with the cheap black bands - upon replacing those with the mentioned bands, they still stand tall on their shelf ;)

Thanks for sharing and all the best,
Thorsten

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12 hours ago, Hod Carrier said:

The other aspect of this which I think is a bit of a shame is that this is the sort of thing that's quite clever but, because it works well, is likely to go almost totally unnoticed when the railcar is finished.

That's great engineering for you. It makes things look easy, effortless.

I love this solution!

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On 9/21/2022 at 9:11 PM, Toastie said:

Brilliant - as expected - solution. What else ...

 

On 9/22/2022 at 8:42 AM, Duq said:

That's great engineering for you. It makes things look easy, effortless.

I love this solution!

Thank you, gentlemen. This is the aspect of the design that I feel proudest of, and the one that I think has the widest possible applications by other builders.

On 9/21/2022 at 9:11 PM, Toastie said:

With regard to the rubber bands: The LEGO varieties (red/blue/yellow/white) "live" much, much longer than the household-type bands. Do you see any chance to use e.g. the red one? It will expand the service interval significantly. I experienced that on the "Technic" Star Wars series droids. They came with the cheap black bands - upon replacing those with the mentioned bands, they still stand tall on their shelf ;)

I suspect that I bought the self-same Star Wars droid set myself and am aware that not all LEGO rubber bands are made equal. The glossy ones are of a different material which makes them less prone to perishing. Sadly I didn't have any short enough for this application, but they are on my list of future upgrades. :thumbup:

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You have been working the black magic of mechanical engineering you have, and I must say, you have become quite the dark wizard. Completely inconceivable design.

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