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Water Crane

DocRef: JC5a

The water crane or column is (for a steam image railway) a necessity.

Placed at platform ends, in goods yards and loco depots, they were everywhere to be seen.

Kits for these are not cheap (is anything in G3) so, if you require a large number, it makes sense to scratch-build. Scratch-building also provides the ability to include design variations (look at photos and even water cranes which appear similar at first sight have several differences upon closer examination).

GWR Water Cranes

The need for these arose out of the requirement to provide examples for Monkton Priors, the exhibition layout of The Gauge 3 Society but other designs can be made using the same materials.

The GWR had a distinctive design of water crane, which was a pattern uncluttered by decorative"frippery" and was purely functional.

It came with variations to suit the positioning, but all had a swivelling arm which could reach a locomotive in a range of positions.

Principal variation was in the swivelling arm : It came in either a straight version or one which "cranked" upwards to achieve the required elevation above the tank filler.

The components used to produce the model shown in the photos were purchased from EMA Model Supplies (suppliers of Plastic Weld, an ABS solvent) who stock a range of profiles, including tube, elbows and spheres which are available in a variety of diameter, angles, etc.

The following profiles are the starting point for producing this water crane [catalogue Nos. in square brackets....the enclosed normal () brackets form part of the catalogue number]

Grey Pipe 12.7mm [VT-16]

Grey Pipe 9.5mm [VT-12]

Hemispherical Head 22.2mm [VHH-28VG] quantity 2

90 Degree Medium Bend- 9.5mm [E-( )-12] quantity 1

45 Degree Bends- 9.5mm [A-( )-12] quantity 2

Flange - 9.5mm [F-( )-12]

Plastic Weld (ABS solvent)

You will also need brass wire/rod 1/16th and 3/32nd inch diameters for the tie rods and rotation lock control rod.

The precise arrangement of the ties which support the swivelling pipe arm depend upon the length of the horizontal pipe. The longest have three anchor points (as in the example here) but those with shorter arms have only the single tie, anchored to the vertical stay. As a rule of thumb, observation of different cranes and a Swindon drawing suggests that the inclination of the long stay is commonly 15 degrees to the horizontal and (where present) the additional component is a 3-4-5 triangle...remember those...shades of Pythagoras! Hence, the lengths of the anchor rods/stays are variables which relate to the length of the swivelling arm, since the inclination of the main tie appears to be a constant, regardless of the arm length.


For the purpose of this construction guide, I will use the dimensions of the example in the photos. Remember that the length of the delivery pipe arm can be varied and the arm can be either straight or cranked upwards. The rules for varying the arm length and associated tie rods are mentioned above.

Cut one length of tube 165 mm long from 12.7 diameter stock (this is the vertical column).

Cut one length of tube 120mm long from the 9.5mm diameter stock (this is the straight section of the horizontal delivery arm).

Cut from the 9.5 mm tubing two sections,9mm and 12mm.

Cut a 6mm thick ring from the 15.9mm tube (this is the base of the vertical column).

From 3/32 Inch brass rod cut two lengths (one 60mm the other 45mm ... these are the stays for the tie rods.)

From 1/16 inch rod cut a single 255mm length (the ties) plus an optional 115mm length (the rotational locking control rod if required).

Take two of the 22.2mm hemispheres and glue together with liberal amount of solvent. Leave the joint to harden overnight since the resulting sphere will need to be drilled in four positions.

Square off the ends of all tube sections, then take the 9.5mm (horizontal arm) tube and glue a 90 degree elbow into one end (this the downward pointing end to which the "bag" will eventually be attached). At the opposite end of the same pipe attach two 45 degree elbows DIVIDED by the 12mm length of straight pipe cut earlier to form the "cranked" section, ensuring these components are PRECISELY in the same plane as the 90 degree elbow at the opposite end and that the cranked section drops downwards at the end where it meets the vertical column (i.e. same direction as the delivery end elbow). Next attach the 9mm straight section to the elbow end. Take the two half-sections of the 9.5mm dia. flange, glue to make the full flange and, when hardened, remove the "collar" from one side of the flange. Next glue the the flange over the tube, with the remaining "collar" towards and flush with, the end of the tube. Put this to one side while the joint hardens. Cut a 2.25 mm wide strip of 1mm thick plastic card of sufficient length to encompass the flange and glue so as to deepen the flange.

Take the vertical column section and the 6mm thick ring cut earlier from 15.9mm stock. Taper one end of the ring, this will be top of the base of the column. Fit the base ring over the base of the column so it is inset 3mm from the base. Next to tackle is the thin flanged ring which sits centred 145mm from the base of the column and there are two (perhaps more) possible ways of dealing with this. One option is to cut a thin, 0.5mm, ring from the 15.9mm tube, glue this to the column and then cut narrow strips of very thin (5 thou) plastic card and wrap/glue above and below the ring. The way I did the first one was to wrap/glue a band of thin plastic card around the column and then cut (from thin plastic card) a ring to fit over the band. On reflection, the first option is probably simpler.

Next we need to tackle the larger flanges which adjoin the swivelling section on the real thing (this model has not been made to swivel but could be if you wish).

Take some plastic card 2mm thick and cut two discs each 19mm dia. and then bore each to slide over the 12.7mm column. Before fixing in position, round-off/taper the edges of one disc; this will be the lower flange on the column. Fix the two discs, so that the lower edge of the lower disc is set 8mm from the top of the column tube and there is a distinct division (not a gap) between the two discs. Next, from thin plastic card, cut two strips each 2.5mm width and of sufficient length to encompass the column. Glue these so as to abut the discs, one above, the other below. Leave the joint to completely harden, then very slightly taper the upper section of column above the discs.

Attention now turns to the spherical component. Firstly, drill four 1mm pilot holes; two to attach the two tie stays (only one if you choose to model a short delivery arm),one for the delivery arm and one other for the attachment to the column. The tie stay holes need to be opened up to 3/32 (be careful when drilling larger holes, do incrementally or you may split the component) and the arm and the column attachment holes are each 6.25mm.

Take the two lengths of pre-cut 3/32 brass rod and file a small notch in one end of each piece (this is to locate the tie rods when soldering). Glue the longer section into the hole which will become the top of the spherical component, such that 53mm is left projecting. Glue the shorter section such that 37mm is projecting. In both cases ensure the notches align with the path of the tie rods. Next cut two 2mm lengths of tube (brass or plastic) to slide over the 3/32 rods and glue to form collars where they exit the sphere.

Next take 6.25mm Plastruct tube and cut two lengths. One needs to be 10mm, to connect the sphere to the delivery pipe arm and the other will be to connect the sphere to the vertical column. If you want a swivelling arm, then the section will need to be quite long (at least 30mm) but only a 15mm length will be needed if the arm is to be fixed. Glue these into the appropriate holes in the sphere, the longer section being diametrically opposite the longer of the tie-rod stays. Cut a 1mm section from 12.7mm tube to fit over the shorter length of 6.25mm tube and glue this to be flush with the open end of the tube. Now use filler to shape a tapered transition between the sphere and the end of the shorter tube (see photo).

Cut a 2.5mm wide strip of thin plastic card, just long enough to encompass the delivery arm and glue this so as to be centred 7mm in from the joint where the 90 degree elbow is attached to the arm. When the joint has hardened, drill a 1/16th hole "top dead centre" to accept the end of the tie rod. Measure and drill a second 1/16th hole 12mm outboard of the first to accept the "hand hold" rod (Note : Not all cranes were fitted with these). If fitting the hand hold then cut an 18 mm length of 1/16th rod and two short sections of tube which will slide over the rod to form the fixing collar and the top of the grip. The rod should be fixed so that 13mm is left projecting from the pipe before adding the collar pieces.

The delivery arm pipe can now be attached to the sphere; it may be necessary to "ease" the pipe bore to accept the 6.25mm jointing spigot. Take the 255mm length of 1/16th tie-rod and bend a 105 degree angle 3mm from one end. Insert this end into the hole in the delivery arm and then mark the rod where it meets the vertical stay which projects from the top of the sphere. Bend so that the remaining length of rod meets the second (horizontal) stay. Glue the end which fits into the pipe and then solder the rod to the two stays. Trim any excess rod and file to tidy the joints.

We are almost there, just a few details now to add!

Where the spherical section is to be attached to the column, you have the option of fixing rigidly (as i have done) or leaving the arm free to rotate. Whichever option you choose, the next two steps are common to both.

Cut from the 12.7mm tube a 2mm length and from the 9.5mm tube a 5mm length. Ease the 9.5 tube to slide over the 6.25mm tube which projects from the base of the sphere, and glue flush with the base of the sphere. Take the 12.7mm ring and ease to fit over the 9.5mm tube and glue flush with the open end. This will leave a length of 6.25mm tube projecting, with which to fit to the column.

If following the "fixed" arm option, you can simply glue the column to the sphere, ensuring the mating surfaces are concentric. If wishing to have a swivelling arm, then you will find there is sufficient clearance to insert a thin wall metal tube of 5/16th inch or 8mm internal diameter, to provide a bearing surface.

There is one more optional fitting : Some, not all, had a locking device to prevent the arm swinging and obstructing tracks. Others relied upon a tether or chain to stop them swinging. If you wish to fit a non-working lock control, the following steps are necessary but I would suggest that you leave this off if fitting a swivelling arm.

From 8mm Plastruct tube cut a 2.5mm length. Below the sphere you will need to file a "flat" in the flange/collar to accommodate the disc. This ring is then glued as shown in the photos. and when hardened filled to form a solid disc (I used Isopon). The disc is then drilled through the centre to take a a short length of 3mm tube which projects 2mm from the surface of the disc.

Next, file into the flanges below the joint a narrow slot to accept the 1/16th operating rod (see photos). Take the 115mm length of 1/16th rod and form a circa 90 degree bend 12mm from one end to form the lever. Glue the upper end into the slot in the flanges. Cut a piece of 2.5mm thick plastic card 3.5mm x 10mm and file a groove to accept the 1/16th rod along the 10mm length on the 3.5mm face. Position the rod/lever into the groove and glue the column, take a short section of Plastruct tube and shape as a handle to slide over the projecting end of the rod.

All that is now left to do is to fix the "bag" to the end of the delivery arm. I used some electrical shrink tube but other materials are equally suitable.

Depending upon where you intend fitting your water crane (e.g. ground level or platform mounted) you will need a different type of base unit, incorporating a drain or drainage hopper, a control valve and perhaps a tethering point for a restraining chain, where there was no locking device fitted. Another accessory is the "fire devil" to keep the water from freezing and some locations had a small coal/ash bunker to fuel the fire.

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Page last modified on February 27, 2018, at 10:43 PM