An American in England

[tedp]

Some time ago, I was given a Langley kit of this, by my good friend and fellow modeller Jacky Molinaro.



source: http://forums.auran.com/trainz/showthread.php?115901-Small-American-Steam-Locomotives&s=4e2de608283c4f4bb7ae08d9ea629350

For some time I pondered on what chassis to use on this model. It was designed for the Farish 4-4-0 chassis which, frankly, makes it look ridiculous due to the inside frames. Scratchbuilding was considered, and another friend even offered to build me a chassis, but at Expong I ran into a Liliput Zillertalbahn jackshaft driven diesel, so I decided to give that a try instead. It ran beautifully, and honestly I was loath to strip it down.

But remembering the work Tom Dauben did on his Kelani Valley Hunslet, I took a leaf out of his book and set to work converting the chassis of the little diesel. The wheelbase is slightly short at 18mm where it should be 20mm, and the wheels are only 8mm instead of the regulation 10 or 11. However, it is a beautifully running outside frame four-coupled chassis, so...



I matched the chassis, and in particular the frame/footplate assembly, against the tank/boiler casting of the kit.





Note the cylinder/front footplate casting from the kit, which would be needing much work. I spent some time measuring various items against each other and decided to use Tom's approach, but for the moment leave the footplate attached to the frames for strength.

I savagely attacked the extremely hard material of the footplate/frames casting of the diesel chassis, with a hacksaw that made short work of the material that needed to be removed.





The front 4-5mm of the footplate was removed to accommodate the cylinder block, which was then cut and filed to shape so it would fit over the frames.



The present status is that the cylinder block and the footplate are made to shape. I will need to narrow the footplate down so it will disappear under the tanks. The slidebars may be attached to this again, but I must first check on clearances, as the cranks are fairly wide. It may well be that the cylinders will have to be moved out a mm each.

I cleared away a lot of material inside the tanks and boiler, but these wouldn't sit on the footplate due to the motor clip interfering, so there will be a slight gap (1mm) which brings the tanks to probably slightly over scale height over the track. But so far it doesn't look too bad if checked against the drawing. Here is the result of an afternoon's work:



Before I forget, the dummy plug for the decoder socket can be laid flat if you remove the plastic collar at its base. The connectors can then be bent at a right angle so the plug won't stick up and interfere with the loco body.

And now I'm off to relax and have dinner!  ;)

[David Hennessey]

Looking good so far!

[rod335]

The Branchlines 'Hawk' chassis fits this kit well and is reasonably easy to assemble.

[tedp]

Thanks Rod, I might have used that but just didn't think of it. This one turned up at Expong, so I decided to use it. It's very smooth and powerful.

[B.Meldon]

This is a good way to motorise this kit and will undoubtable look good when finished and run well.

However it has to be said that the boiler/tank casting in this kit is not the best quality and falls way short of what can be done today. In fact it was not that good when it was first available in the 1980's and needed quite a bit of work to make the smoke box round and the thanks square!  From memory the smokebox also drooped a bit at the front and the rivets on the tank side were small holes rather than small points. The brass parts of the kit are a lot better and tend to show up the casting.

Brian Meldon

[rod335]

My memory of this kit is that the castings are really too thick and in consequence have distorted on cooling. My comment about the Hawk chassis was not meant as a criticism of your choice Ted, merely to be informative.  In the end, almost anything is better than that completely inappropriate,ugly and not very well running Farish chassis!

[Brian Mosby]

This is a good way to motorise this kit and will undoubtable look good when finished and run well.

However it has to be said that the boiler/tank casting in this kit is not the best quality and falls way short of what can be done today. In fact it was not that good when it was first available in the 1980's and needed quite a bit of work to make the smoke box round and the thanks square!  From memory the smokebox also drooped a bit at the front and the rivets on the tank side were small holes rather than small points. The brass parts of the kit are a lot better and tend to show up the casting.

Brian Meldon

when I built one back in 2013 the casting were ok
006 by brian mosby, on Flickr
008 by brian mosby, on Flickr

[tedp]

It is indeed as you say - the smokebox droops a little. The casting is very big, so it must have distorted when cooling. By comparison, the photos by Brian Mosby look much better - did you clean them up? I suppose I will need to do a little fettling, it isn't worse than having a 3D printed kit that needs to be spruced up.

The Hawk chassis Rod mentions should be more appropriate due to the wheel size and wheelbase. One disadvantage of the Liliput chassis is the solid frames and the shape of the cranks. I may try and open up the frames a little so they look less solid, but I have to weigh that against the risk of damaging them.

I'm not familiar with the running properties of the Farish 4-4-0 chassis. I have used one of the 2-6-4 chassis which is very smooth. But I understand quality was a little variable.

[Brian Mosby]

all I did to clean them was a quick bush with a suede brush (brass bristles)

[tedp]

That would account for its clean looks!

I wonder how to turn this into a steam locomotive chassis. I have been measuring the space available for the connecting rods, crossheads and slidebars, and considering what to do so I won't run into trouble. The main issue is that these, and the cylinder casting, were designed with an inside frame chassis in mind. The photo below shows the etch with the parts indicated. The casting has been attached temporarily to the chassis.



Space behind the slidebars
The Liliput chassis has thick frames and cranks. Allowing for the crankpin screws and the sideways play you need to clear a width of 22.3mm. I think it will be safe to put the insides of the slidebar etches 23mm apart. Add 0.3mm for the thickness of the etches, and you will need 23.6mm over the outside faces of the slidebar etches.

This will have to be allowed for by the recesses in the back of the cylinder casting. These need to be filed out - practice will show if it works, and if it doesn't look silly. See photo below - the space indicated with the double arrow must be 23.6mm.



Connecting rods
The crosshead folds over the slidebar but it stays comfortably away of the crankpin since the wheelbase is only 18mm and there is 21mm from the crankpin hole to the crosshead on the etch. However, the slidebar etch won't allow the travel needed for the crosshead, since the connecting rod is too long for the short wheelbase.

Since the connecting rod and the crosshead are in one piece, I might cut them through and re-solder the connecting rod to the outside of the crosshead. Unless it will then foul the crankpin! Again, this has to be measured carefully...

And finally, the screws on the rear cranks are too short to accommodate another rod. So I will have to find a fitting tiny screw of a suitable length... I'll keep you posted.

[Elmgate]

I'm not familiar with the running properties of the Farish 4-4-0 chassis. I have used one of the 2-6-4 chassis which is very smooth. But I understand quality was a little variable.

I have two of the Farish 4-4-0 chassis' operating as 0-4-2T under my ELMGATE and THATCHAM locos. Despite their age, and my modifications, I have never had problems with them. One is the earliest type with brass gears throughout, and the second has "nylon" (?) intermediate and final gears. Neither have I a problem with any of my other Farish chassis. That said, the latest Bachmann versions are IMHO, superior. I am sure, as discussed elsewhere, that clean track and proper balance of the body has a lot to do with good running, whatever the chassis.

[tedp]

Thanks, Tim - what you say about track and balance is similar to my experience.

Balance is very important. At the moment, the Liliput chassis is overloaded at the front end if I put the boiler/tank casting on it. As a consequence the rod-coupled front wheels take most of the load instead of the driving wheels at the back. This shows in slight jerkiness. I will balance the model slightly towards the rear to reverse this. The same effect is apparent in the Backwoods chassis - the rear wheels must take most of the load, about 60 to 70% will work best.

[B.Meldon]

I totally agree with the comments about this needing about the same work as a many of the 3d prints do but white metal can be so much better than this.
As to balance it looks like there is lots of room in the cast tanks and firebox for extra weight to balance the loco and from memory the cab roof is cast metal as well.

Brian Meldon

[rod335]

Putting weight in the tanks will do nothing to balance the loco, only make it heavier overall. The point of balancing this loco is to counteract the weight of the (cast) smokebox and front apron. So weight will have to be fitted BEHIND the rear driving axle.

[tedp]

I agree the additional weight should be far back - there is little extra weight needed as it has plenty of weight already. There is plenty of space in the bunker. However, this may introduce a tendency for the loco to sway around the short wheelbase. I'll have to experiment and see what's best.

Today I did some further fettling to the front end block. I cleared the recess in the cylinders to the required width and then epoxied the block to the frame and footplate casting. The cylinder centres are slightly above the wheel centres to correct for the small wheel diameter. I also made the slidebar frets to size.



Here is the slidebar fret glued to the cylinders and the frames. Note that I introduced a slight angle to make them line up with the driving wheel centre. I folded the supports so they rest on the footplate of the Liliput chassis. There is about 1mm to spare between the crankpin screws and the fret.







Next, I turned to the connecting rods. These are thick at 0.3mm, and the crankpin holes are matched to the Graham Farish wheels, about 1.7mm diameter. So I decided to ream them out to 2mm to accommodate the screw head, and sweat on a thin backing shim of only 0.1mm. This is drilled for 1.1mm so I could try and re-use the original crankpin screws on the chassis.





Next, I tried fitting one connecting rod to the loco. Some extra space was needed on the slidebar fret to enable the crosshead to slide the full length, but I assembled it and it seems to work. It runs without binding.



The only problem proved to be the crankpin screw. This didn't like the extra thickness after all - it even decided to turn wild in the tiny thread of the crank, so I put in some superglue to fix it. I will need to run the chassis upside down on the workbench for some time to see if it will hold! But it starts looking good, I think...