Dutchiedoughnut

PF powered steam tank engine

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A while ago I was working on an early design for a class 4mt 2-6-4 tank engine. Such a design is difficult, because all of the PF elements have to be concealed in a very small container. I am rethinking a class 4mt, this time starting from the Lego PF components and building the engine around it. I started from the drive train used in the class 08 shunter.

Steam%20engine%20and%20PF_zpseesghrm7.jpg

Clearly, there are no details added and it is only a rough start. The whole drive train is there though - battery box, IR receiver and M motor.

The battery box is hidden inside the boiler, while the M motor is clearly shown where the firebox would be, roughly. The M motor can be rotated 180 degrees to sit inside the cab to create a lower profile locomotive. The boiler itself is 6 wide and the design should lend itself to 6, 7 or 8 wide designs depending on details. I will most likely go with 7 wide to match it to my class 08.

This model is likely to be a class 4, 2-6-0 with tender, but all PF is going to be inside the engine.

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I love the compactness of the design. I assume the battery box is in front of the motor, and the PF Receiver just peeks out the top flat part.

Would you mind showing how this would drive the wheels? Do you have any concerns on how many coaches can be pulled from an M motor?

Cheers

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I like it already! why do you actually want all the PF stuff in the locomotive itself? if its a class 4 the receiver and battery box could be easily hidden in the tender and the M motor in the locomotive itself. and if you need a a smaller tender you could hide the receiver in the cab! this obviously makes cab interior impossible but sometimes... the cables of the components are pretty long so you don't need to worry about that!

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Well, I wanted to see if it is possible. For a tank engine it won't be possible to hide anything in the tender.

If we have more options for a very small drivetrain it opens up so much more designs :).

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4mt%201_zpsw2npesqn.jpg

Here is an update for the 4mt, showing the overall shape :).

The drive train is nearly a copy of that used in the class 08 shunter:

Class%2008%20drive%20train%202_zpsn56lhntf.jpg

Edited by Dutchiedoughnut

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I love the drive train in this, I have never been able to get a compact drivetrain to work reliably enough so I shall give this one a try on a South Australian Railways F class tank engine I am working on.

Thanks,

Rob

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Well, most of the rough structure is done now :). I've moved the first drive wheel forward by one stud and I've added the front of the locomotive. I've tried to made it resemble an early 4mt, which has a different front end than the latter ones. The running gear is missing, that will be next.

Class%204mt%20Ivatt%202_zpsd3awhoeb.jpg

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If we find a big wheel, then your power plant, will be able to build here is a locomotive. If you do not mind.

1big.jpg

And if you do not find the big red wheel is built with the same powerplant another locomotive. :classic:

2-8596_-8_______01.05.2009.jpg

Edited by Nemo57

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I'll get back to you, Nemo57 ;).

The Class 4mt is pretty much done :o. Once I figured out how to deal with the cylinders, the bricks sorted themselves out :D. Here it is:

Class%204mt%20Ivatt%203_zpsfyjec9ok.jpg

The end result is a steam engine that's about 26 bricks long (only 6 longer than my Class 08!) and 7 bricks wide. It's 9 bricks wide at the cylinders.

Let me stress - it's SERIOUSLY small! And, the cab is completely empty, ready for lots of details and a fireman and driver.

Are the cylinders in the way of - you know - making a turn? That's what I had to figure out. Lots of Lego steam engines have tiny cylinders to squeeze them in between the boiler and front wheels. I decided to split them - the lower half turns with the leader wheels and the top part is fixed. It looks pretty good to my eyes even though its a little strange in a turn:

Class%204mt%20Ivatt%204_zpslquvmnin.jpg

On a straight track it looks like the front wheel is hidden behind the cylinders, which was what I was going for.

Here is the rough shape, I can start adding details and let's not forget a tender!

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4mt%20260%20and%20tender_zpsvuxmv5qa.jpg

I couldn't resist adding a tender :). Also, the engine has been painted green, it looks much better :).

About the tender. I started out with a 3 axle tender to follow the real world train, but it looked too short. I tried 3 axles on a longer tender, but that still looked wrong.

So, it turned into a 4 axle tender. The wheels are articulated as one would imagine.

There is a tiny gap between the tender and engine, only a single stud. I managed to do this with some creative use of articulation. In any case, it looks great and it looks like a single vehicle :).

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Man it looks so cool! Very realistic and also extremely compact!

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A bit of an update :). I got around to detailing the cab and tender!

The cab features controls for (what I imagine would be) the regulator, reverser and brakes on the driver's side. On the stoker side, there are some more controls for the injectors and of course the firebox doors. The tender has a shovel, a lever to operate the door to the coal bin and a gauge to show how much water is left in the tender. The door to the coal bin is halfway open and there is some coal at the bottom. These are normally painted black, but are painted grey so they can be easily seen on this picture.

4mt%20cab%20details_zps18gox9t5.jpg

And there is a bit of an update to the front and back of the engine. I've added headlights and looked to British videos for inspiration. The Jacobite in particular was running with a center headlight and the outer ones turned off, so I figured I have to have three lights. I also added a boiler door at the front as the front looked too massive and huge.

4mt%20buffer%20details_zps7fxgqlyy.jpg

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how did you get it on rails? LDD doesn't let me do that.

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I had to turn the wheels by hand ;). When I did that, LDD was ok with it.

I put a 2x4 brick between the engine and the rails to align the wheels visually. I manipulated the joints until it seemed the wheels were in the right place.

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I just realized something, your loco doesn't have couplings. if you want those older detachable couplings you can find them under the name 'coupling lever' and 'magnet'.

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2-6-4%20tank%20nose_zpsr4dulf2f.jpg

I love the 2-6-0 class 4mt. However, I did promise a tank engine and I set to work adding the water tanks and rebuilding the nose to match the tank engine nose. It'll be a 2-6-4 this time and if you look closely you'll see small differences left and right. The boiler is 1/3 stud smaller and is set a bit lower. I had to lower the battery box a stud to achieve this. I think it looks really nice though, more in line with the actual 2-6-4 on pictures.

I've added the water tanks but I don't like them yet. They are way too square for me. Also, I can only see pictures of a black 2-6-4. I need to get my paint brush!

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That is looking really sharp (well, that family of locomotives to be more precise). Very clean lines and just a nice looking, well proportioned locomotive. Splitting the cylinders the was you did was brilliant. Is there any chance you can align the cylinder exhaust pipes with the stack? It is hard to do on lego locomotives, but since you've split the cylinders it might be possible. The details in the cab are nice too. Have you considered using the 1x1 round plate with flower edge for valve handles?

33291.gif

Looking at the mechanicals, you will probably want to build those up in real brick and test how they work. There is a lot of slack in the rods that could cause problems. It looks like you have a 5 long technic half beam that is only pinned to the front wheel and a 6 long that is pinned to both wheels. Then the connecting rod to the cylinder is held in by either a standard pin or a long pin, but in either case it looks like it is off by half a pin (perhaps sticking half a brick inside the wheel). That will likely cause unnecessary friction. The other end of the connecting rod is not connected to the axle pin, but probably better to use a half pin. All of these seem easy to fix if you build up these details, e.g., you could use an 11 long full technic beam for the connecting rods across the wheels and then test it to make sure there are no problems. You will also want to test the clearance on the underside, you have a risk of catching switches or grade crossings with the lowest level of plates. The ball couplers might also prove to be problematic if you run on uneven layouts... still might be fine but probably worth testing to make sure.

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