PWZ Drop Centre Wagon.

All railways around the world are faced with restrictions, the main two are the width and high of the loads they can carry. Rail networks are packed with bridges, tunnels, awnings, platforms, tracks side by side, etc. which restricts what can be carried. Another issue is the weight of a load. Most Rail Operators track network will have a set carrying capacity, or may have track with different carrying capacities. Before the 1970’s, QR had three classifications of track, 15 Ton Axle Load (TAL) called “A” class lines. Branch lines with lighter rail had a 10 TAL which was a “B” class line. Some western main lines had a “Some “B” class Line” that was rated at 12.5 TAL. The QR loading gauge allowed for 9ft 4 in wide loads above platform level, loads up to 11 ft 6 ins wide could be accommodated with restrictions. The 1981 metric loading gauge will be included below.
 
I.e. Brisbane to Roma “A” Class Line 15-TAL
Roma to Charleville “Some B Class Line 12.5-TAL
Charleville to Cunnamulla/Quilpie. “B” Class Line 10 TAL.    

Prior to 1959, QR had very little rollingstock for loads over 24 tons in weight or for loads that were just outside of the loading gauge in height. There was the six wheeled PJW Drop Centre “Well” wagon and a wooden PJM wagon where the floor was recessed into the underframe. Some information on the PJW wagon can be found back in September 2019 Blog where I build a model of the wagon. 

PWZ 31608 entered service in 1959. Tare weight of 26 Tons 17 cwt and could carry loads up to 81 tons with allowable overload on “A” class lines subject to position of the load and travel speed. The wagon consisted of two bogie subframes with 2 pair of QR 9 bogies (4 axles each) with 12-ton axles. Between the two bogies unit was a 43 ft 6 in Drop Centre frame. The well could accommodate a load that was 19 ft 4 ins long. The well had a false wooden decking of 2 in. hardwood. Each end of the frame also had 1½ in. timber decking. Over all the wagon was 66 ft. 11in. long over buffers, that is 3.9 F for marshalling trains. 

Both bogie unit were fitted with 8-inch A.F 3 brakes cylinder and one bogie unit had a chain type windless hand brake. When new the wagon was fitted with Premium class draw hooks with fixed couplings and was painted black. 

Sometime after 1969 the wagon was painted grey similar to all other goods/freight wagons. 1974 the wagon was allowed to travel at 80 km/h when empty, A red circle with words “When empty” was added to the wagon.  During 1980 the wagon hooked drawgear was replaced with auto couplers, the classification was altered to PWZ/T.

 

Loads for the wagon was largely transforms, and heavy machinery. At times the wagon carry machinery on branch lines that was to heavy for conventional wagons. During the Main Line Electrification Project (MLE) in the mid 1980’s the wagon was heavily booked for transporting transforms to Central Queensland. At times the wagons were used to carry coil steel and bridge piers, boilers etc.       

Over all the work for the wagon was not that great outside the MLE Project, between trips the wagon would sit empty in Roma St and in later years at Yeerongpilly. During the early 2000, the wagon was store at Hamilton. Around 2011 the wagon found a new home at the Pioneer Steam Railway at Box Flat. 

Around 1973, the business group went looking for the PJM wagon, to cut a long story short, it was traced to Ipswich Workshop and found that it had scrapped. It was also discovered and news to the business group that the workshops were going to build another PWZ wagon to replace it. The business group was able to have input into the construction of the new wagon. Given the country had just transition from imperial and metric, larger metric material was used in the new wagon.
 
PWZT 38287 has the same overall dimensions as PWZ 31608 and entered service in December 1974. It looks the same, (there are noticeable differences other than the bogies) but can carry a heavier load. The Weekly Notice referred to the wagon as the 122-tonne gross Drop Centre Wagon.  The wagon bogies are QR 33 and the tare is 31.2 tonnes. The normal capacity is 82. 2 tonnes, but can carry 91.4 t with the centre decking removed. The bottom of the drop centre sits just 114 mm above the rail; the top of the timber decking is 445 mm above rail.
 
Request for the use of the wagons must be made to the O/C Out of Gauge Loading care of General Manager SED and Chief of Operations Brisbane. The approval of the Chief Engineer must be obtained in each case where the gross mass exceeds 101.6 tonnes, while the approval of the Chief Mechanical Engineer and Workshop Superintendent must be obtained in each case where the gross mass exceeds 113. 4 tonnes.
 
Both wagons have 12 lashing shackles on each side for securing the load. At times bracket were welded to the frame to assist with securing the load.    

As much as possible the loaded is to be marshalled on the engine, if this cannot occur for some reason like track capacity, wagons between the engine and the loaded PWZ must be loaded to over 75% of their carrying capacity.  Supplement to the Working Time Table also has a list of restrictions for a loaded PWZ, I.e. the Albert Bridge (the older bridge) at Indooroopilly.

Loaded movements of the wagons was generally covered on a Train Notice detailing track sections the wagon must travel on or cannot travel on, marshalling, speed of train, checking in route, crossing or passing trains on other lines.  

  

The wagon body could be transferred to road to save double handling.

The loading gauge spreads out to 9ft 4 ins wide above platform level, that’s around 3 ft above rail level. 1981 metric loading gauge below.

A loading gauge for your layout can be a handy tool for building loads on your wagons. All railways, prototype or model have their limits.

Instead of the second PWZ, the business would have preferred two 8 wheeled well wagons that could carry an over-high 20 ft container.  

During the Main Line Electrification program in 1986, a fourth wagon entered into service to carry smaller transforms for the program. This was PT 25588 wagon, a 1982 modified PCE wagon converted from a CMIS wagon. The wagon could carry two transforms mounted below floor level. When not required for transforms the wagon could be used to carry one 20ft container. The wagon was fitted with QR 20 bogies, auto couplers and could carry 25.6 tonnes on express freight trains (Red Circle).  Most PCE wagons were written of around 1993.   

A number of transforms came out of GEC siding at Rocklea for interstate destinations on NSWR beam wagons.

The shunt moves for these wagons into and out of the GEC siding was carried by a QR shunt engines.

The move was carried out using the GEC donkey wagon. NSWR locomotives were not permitted to cross over the bridge into Commonwealth Engineering. I heard various stories why not, I never found out the correct reason. There was a restriction on the bridge when the 3100 & 3200 class electric locos were delivered, but a 48 NSWR would have been well under that. Today PN shunts the siding with 81’s and NR locos, I guess that blows the bridge out being the issue. Another was the curves were to tight for NSWR locos, they were OK for QR 90 ton locos. NSWR locos would to up to the dual gauge track and not any further, I think it was more an industrial issue. Before my time there was a section staff for the branch.  

Note the offset coupler for standard gauge wagons. The wagon didn’t have any brakes. A bypass air hose was used to for the brakes on the beam wagon. 

Model.

I recall in the late 1990’s, a PWZ wagon was in a model contest at the Brisbane Model Train Show. The wagon was built by the late Peter Ford. A couple of years ago the wagon was still in service on a layout in Brisbane. Just recently, I learnt that was to be a kit but was never released.  

My model was scratch built using styrene sheet, Evergreen scribed and strip styrene. The bogies are AR Kits 2CL narrow down for 12 mm wheels set. For this wagon, spoked wheels were a must have. I didn’t have any spares, then the penny dropped there were some on old wagons in the cupboard that have been removed from the layout, the spoked wheels were swapped out with disc and used for the project. 

Plumbers lead was packed in under the floors to give some weigh for when running empty. 

AR Kits 2 CL bogies modified for 12 mm operations. Steam Era brake shoes were added for extra detail. Bolsters were cut from K & S brass KSMETALS SKU 8262Rectangular Brass Tube: 3/32" X 3/16" x 0.014" Wall x 12" Long

Caintode Flats buffers, AR Kits brake cylinder and reservoir. Air pipes were formed up from 0.03 mm bass wire. Securing shackles were bent up using 0.03 mm brass wire.

 The transformer load was scratch built using styrene sheet and strip. The general shape was taken off a photo above with some modellers licence. The transform is a press fit onto the wagon and can be removed if required for other loads down the track in the future. The issue was securing of the load, most of my loads are secured with chain, the chain is also secured to the wagon, thus the load cannot come off the wagon. Watching a YouTube video produced by “Class One Model Works” fixing one of their transforms to a well wagon they used rod. It appears in the US steel rod was welded to the load and wagon to secure the load. Maybe I could use 0.5 mm brass rod, the rod was attached to the transformer and directed towards a securing shackle on the wagon, but not fix to the wagon. Painted black and it looks the real deal a couple of feet away. I guess there is nothing stopping you from attaching chain to the rod for a better finish.  

The sign is decal printed on my inkjet printer, the decal paper was from Amazon, it arrived the next morning.   

A freelance transformer was built for the PJW as an interchangeable load using styrene sheet and Evergreen strips/tube. 

The two wagons can be viewed running in service on Westgate as part of the Rocklea shunt train 568 in the YouTube video on the 1620 class locomotives. 1645 was the Rocklea general shunt engine from 1972 until 1979.

Down the track.

Some good news, Amby West has been accepted to exhibit at “The 2026 RMCQ Model Train & Hobby Exhibition. The venue is the South Pine Sports Complex, Cribb Road, Brendale on over the weekend of the 10-11^th of October. The shunt engine for the weekend will be 1645, it has just returned after a few years of service in the west. Operators are most welcome to come along to joint in the fun and try their skills at shunting. By all means, come and say good day and have a chat as well.    

Until next time, have fun and enjoy the hobby.

 Arthur H. 

Acknowledgements.

QR Plans, Weekly Notices, Supplement to the Working Time Table, General Appendix’s.
AMRA Qld Library
Photos from various Modelers and Historians
P. Kennedy O/C Out of Gauge Loads.

Queensland State Library.