Bicentennial MHO -part 4: when is an MHO not an MHO?

Prototype

I’ve been looking at the history of the original carriage. It seems to have been through nearly as much as my model. Originally built as MHO 1875 by Richie Brothers in 1948 under contract 15/43, as a 19.66m (65’6″) 42t wooden-bodied brake van with a centrally located guard’s compartment and load capacity of 20 tonnes. Life was uneventful until 1974, when it had upgraded guard’s accommodation fitted and was recoded MHO 2603.  In 1978 it was wired to work with 415V AC cars, which drew power from a separate power van for use on the main line expresses and was recoded MHX 2603. This explains the ETH (electric train heating) conduit in view on Jim’s photo and made it ideally suited for the later conversions. It became AAH 2603, with the fitting of end doors, a small workshop and a compressor in January 1977 for use on the Queen’s Silver Jubilee Travelling Exhibition train but was replaced by another carriage after a few months. Identity restored to MHX 2603 in April 1978, it remained in service, having roller bearing bogies fitted in 1984 (and being recoded MHY 2603), again modified for the Bicentennial Train in January 1988, it was recoded SRE 2603 but was never used for this purpose. The paint job was obviously too ghastly, even for State Rail. It was condemned in June 1989.

The second crack at being MHX 2603 at Albury in December 1978, the handrails along the sides have gone and the ETH conduit cab be clearly seen.
Photo from Rob O’Regan collection, used with permission. http://www.robx1.net

3801 North Adelaide
The Bicentennial Train in North Adelaide, sans SRE 2603
Photo by Bingley Hall, on Flikr

As best I can tell the Powerline model is of the MHOs built before 1943, and is presented in a pre-1962 modification condition.


The Model

This post was going to be  just about the underframe, but as I started doing things it slowly dawned on me that I’d have to work out where the roof screws went through the floor, and to do that I’d have to do the interior as well.

Interior

These carriages are internally lined with tongue and groove boards, mostly laid horizontal apart from the walls separating the guard from the mail. They are cross laid for strength, vertically on the guard’s compartment side, horizontally on the freight side.  I’m using Evergreen styrene v-groove in 0.08″, that translates to a bit under 7″ in full scale, so is near enough for the overall impression. I’ve scribed the vertical planks on the back of the dividing wall at the same spacing with a scratch awl.

MHO 2609 in Tenterfield Railway Museum
MHO 2609 in Tenterfield Railway Museum
Heritage NSW website

In a clever bit of design, all doors slide into pockets so if the load shifts it won’t jam the door. I’m going to use this to cheat a bit with the doors in the guard’s compartment, I used the offcuts from the doorways to make the door pockets and have left it looking like the doors have been left open, each door is just a narrow strip coming out from the pocket. There probably should also be a shelf that runs around the sides, level with the top of the windows in the MHO, but I can’t find anything about it being in the SBE so I’ve left it out. It can always go in later. There’s also a dividing wall that separates the guard from the dog box and coffin box, I’ll be using this area for the circuitry that controls the lighting. Interior lighting only, there isn’t enough room for the circuit board and a LED with the fibre optics for the marker lamps.  More on the electronics in the final post.

DSC03379a

Interior showing the holes for (left to right) the electrical wiring, roof mounting screw, handbrake and the other roof screw. I haven’t finished painting it yet.

The guard gets a couple of comfy chairs, light and power switches, brake and electrical piping and pressure gauges and a brake wheel. When built, the brake wheels were horizontal, some brake vans had them moved to vertical at some point. I’m going to do this one horizontal just for the hell of it. The wheel’s an etching, I’ve turned the post from a bit of brazing wire using the drill as a lathe and a file to shape it. The interior is done in Humbrol Lining Cream, based mainly on the photo of MHO 2609 above.

DSC03382a

Inside of the roof, mounting blocks, electronics and the LED module.
If the current draw is too high, I’ll pop the outside LEDs off.

The roof just needed minor tweaks to fit, I had to sand a little more of the old window residue to allow it to sit above the door pockets and internal walls. The mounting blocks had to be trimmed to fit entirely within the roof, then drilled and glued in place. There’s a 1/8″ nut glued at the top for the machine screw to go in to. The screws have to be custom cut to length to make sure it doesn’t split the roof.  I also had to carve a small groove for the wire for the lights in one of mounting blocks. Finally, the holes were drilled in the floor. I’ll try to hide these behind a load.

Underframe

Continuing with this project, I really get the feeling that Powerline had a perfectly good MHO and couldn’t resist jumping on the 1988 NSW Bicentenary bandwagon. The closer I look, the more fudges I see. I’ve already had a whinge about the doors, the way the guard’s compartment is internally reversed, the paint job and how one of the Bicentenary stickers isn’t straight.

So today’s whinge: the supplied bogies are 2BCs, which are correct for the earlier 1920s and 1930s contract MHO that the base model is taken from, but from new MHO/MHX/MHY/AAH/SRE 2603 was on 2BLs.


2BC bogies as supplied on the carriage.


Correct 2BL bogies. Both photos from Rob O’Regan collection, used with permission. http://www.robx1.net

I’m going to ignore those for now, possible forever. The toy-train looking wheel sets were replaced with appropriate 10.5mm Steam Era wheels on a 25mm axle. The other thing to note is that the side rails on the frame in the above photos are shaped like “Γ” with a vestigial bottom plate, but on the model they are “[” shaped instead. I might correct that on the KB I’m working on now.

I’d been wondering for a while how to get the power from the rails to the lighting circuit without causing derailments due to wires stopping the bogies from moving freely. When I was washing the bogie frames prior to painting, I realised the centre pin on one was just about broken through. I cut off both pins, filled the holes in the bogie top with PlasBond and drilled new centre holes for 1/8″ machine screws. I’ll attach the wiper from the wheels to the screw, and take the power from the top so everything will be symmetrical and there won’t be any uneven loading.

DSC03376a

Bogies and underfloor upside down, you can see the electrical wiper test fitted on the bogie on the right if you look at the embiggened version by clicking on the pic.
I’ve made painting stands using 1/8″ bolts with a nut immediately above and below the floor to secure it at a comfortable level without it falling off. 

On to the underfloor detailing. The existing underfloor detail is dreadful. The truss rods are too thick, battery boxes and things are in the wrong spot and get in the way of the brake pipes and rods. It was so bad (and damaged) I took the lot off with a chisel and started again using an ILM kit. I’m not completely satisfied with the truss rods, they’ll do for this one and I’ll look at better solutions next time.

The old round buffers were removed, and a new wide buffer fitted to each end. This was fabricated from styrene with the pattern taken from a perspective-corrected photo of an MHO in service, printed out at HO scale.

DSC03378b

Underfloor detail, after painting and washes but before weathering, the Kaydee on the right will be replaced with a long-shank model and the gear box moved back to the right position.
It’s funny how things that look straight in real life look crooked in the photo.

The brake pipes, truss rods and electrical heating conduit were done with fine brass wire, chemically blackened to not show through if the paint gets chipped off at any time. Due to the guard’s compartment being reversed, but the underfloor not being, some of the plumbing doesn’t make much sense – the pipe is on the opposite side of the floor to the guard’s brake wheel that should connect to it.

I made a simple modification to the side rails too, the bracing on the sides of the frame are rectangular rather than triangular, but that was an easy job with a craft knife. This was important because one of the differences between the SRE and the standard MHO is the addition of running boards and electrical conduit under each door. The MHO only has a single step under the guard’s door.

Paint on the bogies and underfloor is a base coat of Model Master Naval Aggressor Grey, it’s lighter than I wanted but was the only spray tin I had. I still don’t have the airbrush functioning. That was finished with a mid-strength wash of Humbrol Panzer Grey and an even lighter wash of Humbrol matt black. Brake shoes in Humbrol BR Lead, other detail was then picked out in white and the edge of the buffers in yellow. The rest can wait until the weathering is done.

References

ARHS Australian Railway History April 2012 http://www.arhsnsw.com.au/arhextras/1204arhwe.pdf accessed 15 April 2014

The Railmotor Society, A Brief History of NSW Railmotorshttp://www.railmotorsociety.org.au/rm_history_frame.htm accessed 15 April 2014

Cooke, D. et al., Coaching Stock of the NSW Railways, Volume 1, Everleigh Press, 1999. Pp182-7


Other parts of this series:

Bicentennial MHO -part 1 – the tale of woe. A rattling parcel arrives.

Bicentennial MHO – part 2 – the power of putty. Getting the bits stuck back together.

Bicentennial MHO – part 3 – up on the roof again.

Advertisements

One thought on “Bicentennial MHO -part 4: when is an MHO not an MHO?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s