Home  ·   Reference  ·   Roster   ·   Photos   ·  Inventory   ·   Contact us   ·   Links





Aster Jumbo

a review and essay by Jerry Reshew




Scale/Gauge:  1/32, No. 1 Gauge (45 mm)


Length O.B.: 457 mm (18 inches) 

Engine 252 mm (10 inches) + Tender 195 mm (8 inches)

Width: 74 mm (3 inches)

Height: 125 mm (5 inches)


Wheel Arrangement: 2-4-0

Driving Wheels: 63 mm

Leading Wheels: 34 mm

Tender Wheels: 34 mm


Weight:  2.6 kg (5 3/4 lbs)

Engine 1.7 kg (3 3/4 lbs) + Tender 0.9 kg (2 lbs)


Axle Driven Pump:  Pump Rum 5 mm x Stroke 5 mm, Mounted on Trailing Driver


Engine:  Two Cylinders with D-Slide Valve

Bore 10 mm x Stroke 20 mm

Valve Gears:  Slip Eccentric Valve Travel 4 mm, Cut-Off 75%


Boiler Type:  C-Type with five fire tubes (Dia. 8 mm)

Water Capacity: 80 cc at 70% full

Working Pressure:  3 - 4 kg/cm


Burner / Fuel:  Two Wick Tube Alcohol Burner

Tender Water Tank:  Capacity 160 cc, Hand-Pump Mounted.

Fuel Tank:  Capacity 65 cc.

Minimum Radius:  1 meter (Dia. 2 meters)




The locomotive which ASTER selected as their 1999 offering is an example of the London and Northwestern Railways Improved Precedent Class 2-4-0, lovingly referred to as the Jumbo in all of the British literature.  This class was the premier passenger design of the period, being powerful and dependable in short haul operation.  One hundred sixty six of these locomotives were erected at the Crewe works in the late 19th and early 20th centuries.  The example, which we are modeling, HARDWICKE, having been introduced on the line in 1876. 


HARDWICKE represents the most elegant departure from the very colorful locomotives of the period in that it is finished in the traditional LNWR “blackberry black”, a deep, almost liquid appearing finish.   

The lines of the class were truly elegant in the best Victorian tradition and many writers suggest that there is an element of Grecian classicism in the design.  The model was designed using the drawings of the original locomotive, and British enthusiasts Andrew Pullen, Ted Leech and Barry Applegate measured HARDWICKE at the York Railway Museum against the drawings.  The result is an exceptional model, which is an excellent runner and exquisite work of art.   


HARDWICKE is one of three Aster Jumbo’s available; NOVELTY (a red and black model) and SNOWDEN (an all black model) being the others. 



The kit arrives packaged in a cleverly arranged cardboard carton with a pebble grained high quality finish and separate interior boxes for component parts.  The first impression is that if the locomotive lives up to the level of the packaging you certainly have purchased a winner.  And you have! 


It is more important that the kit be reviewed against the instructions manual (a 38 page large format booklet) and the building diagrams (12 pages).  I found that the building of the kit is the fun part of owning a locomotive and that the slow and steady approach is the way to maximize the enjoyment of the investment that you have made.  In this kit you will have to pay particular attention to the instructions and cross reference them to the diagrams, while holding the part referred to and thinking about how it all goes together.  I’ll work along with you as we go through the elements of assembly and you can avoid some of the pitfalls, which might arise.  


The instructions are really not as clear as they should be, and they are downright wrong in some parts, but the assembly plans will help you over the hurdles.  Be assured that the result will be worth the effort and the cussing which you are prone to do at what might seem a diabolical scheme to drive you over the edge is part of the fun. 




The kit provides you with a basic set of tools, but you’ll need some other things to make construction easier.  As set of miniature screwdrivers, a fine point tweezer, and a pronged pickup tool are essential, and you’ll also need an artist brush.  


The kit supplies the wheels for both the locomotive and tender with stainless steel rims and hubs.  The model will be immeasurably enhanced if the wheels are painted black to the tread, and the hubs need this treatment as well.  The tender buffer beam also should get this repaint.  The photo of HARDWICKE on the cover of the Assembly Illustrations shows the locomotive, as it should appear.  While the kit contains a tin of lacquer which can be used for this painting, I decided that lacquer is a bit tricky and that I’d go with enamel.  If you take care of this wheel painting at the onset, they’ll be waiting for you and ready to go you when reach the step in the sequence in which they are called for. 


I used Floquil™ Zinc Chromate Primer #110601 first, and then applied Floquil™ Boottopping A/N 514.  It’s a perfect match and your brush can be cleaned with mineral spirits.  Save the lacquer for touching up scratches.   


Aster includes a tube of caulking with the kit and I think that it is OK, but I prefer to use 3M™ Marine Grade Mildew Resistant Silicone Caulking where sealants are called for.  It just seems to be a smoother and easier to control adhesive.   


The instructions call for use of Loctite™ 222 on all screws.  You’ll also need a to get a tube of Loctite™ 271 (or equivalent) and a tube of petroleum jelly (or lithium grease).  Read, and then reread the first couple of pages in the instructions so that you’ll feel comfortable with the project.   




Here’s where you get your first scare!  The first thing that you are asked to do (in Section 1) is to identify the block and point the 3 holes to the front and 2 holes to the rear.  They meant to say that the 3 holes are on the right and the 2 holes are on the left.  I’m sure that the engineers who wrote this just wanted to see you are paying attention.  Follow the instructions from here on, but I found that it’s a good idea not to interchange the pistons in the cylinders.   Lay the pistons aside in such a way that they will go back into the cylinders that held them when you opened the package. 


Polished slides and valve seats are the key to smooth running, so pay particular attention to his part of the construction process.  It’s kind of simple-minded fun, but the finished pieces should be mirror like. 

The instructions are straight forward, but you should pay particular attention to the piston rings – be sure do this step with delicacy so as not to damage the rings.  A bit of petroleum jelly applied to the rings before slipping them over the piston will protect them. 


I found that the slide bars (part 2-5) were a poor fit and required a bit of filing to get a smooth sliding fit on the crossheads.  When you’ve finished with the cylinder block, you have actually completed the operating part of your locomotive and now you feel that the rest should be easy – it is! 




The block is supposed to be a slide fit between the frame, but I used a plastic faced hammer to get it in place.  The alternative would be to file away some of the block (or the frame) but this didn’t seem like the way to go.  


The lubricator assembly is the step which might set you to thinking!  The pressure fit of the oil pipe into the block is something I don’t like.  The integrity of the installation depends on tightening the assembly into the block using nuts pressing on a frame plate.  The silicone O-ring (PS-2) should have a dollop of petroleum jelly applied to protect it during the installation.  The lubricator will fit in the frame but it will need some urging and pipe bending, with a few small taps of the plastic hammer thrown in.  I consulted with Andrew Pullen about this arrangement and he informed me that he modified the lubricator by silver soldering the oil pipe into the block.  This undoubtedly gives a secure connection, but I think that you can get a workable unit by being careful not to damage the small O-ring when you assemble the locomotive.  




The locking arms (par 3-17) must fit smoothly and snugly between the ends of the valve rods.  I filed these parts until the fit was loose enough to work, but not enough to be sloppy.  The instructions are clear and you should have no trouble with the wheels if you refer to the drawings as you go.   


The eccentric on the rear drivers was out of position when it was time to install the Scotch crank assembly, but this was easily corrected by loosening the grub screw and sliding it into proper place. 


The O-ring on the feed ram is quite delicate, so application of the petroleum jelly will help in keeping everything intact.   


Installing the buffer will finally put your locomotive on wheels and prepare the way for the setting of the valves.  Before attempting this step, roll the locomotive back and forth a few times to make sure that all is operating smoothly and that there are no squeaks – all moving parts should have been oiled during the assembly process, but if you missed a few spots you can correct that oversight at this time.  It is also critical that you remembered to Loctite™ the small pins which connect the wheel eccentrics to the block assembly (Parts 3-26 &27).  I forgot to do this and had to take the locomotive apart after a couple of runs. 




Timing of the valve sequence in this locomotive is not complex and the instructions and diagrams are excellent.  The photographs, which are included, are virtually useless, but the key element is the sparing use of sealant so as not to gum up the moving parts.  Apply a touch of Loctite™ to the P1 grub screws before you seal up the valve chest, but make sure that the valves open equally in forward and reverse before the cover is fastened in place.  You now get the chance to try your work on air pressure, it will run!  Follow the instructions as to setting up the air test, and be sure not to run the engine for more than a few seconds since there is no lubrication of the pistons and valves at this time.   


Any source of low-pressure air can be used, but a simple method is to obtain a portable air tank at your hardware store and fill it at a service station air pump.  The tank will give you enough air to do all the testing that you will require.  If the engine doesn’t perform smoothly, this is the time to make adjustments to the valve setting. 


It is a prudent procedure to review the steps, which have been finished to make certain that all screws are secure, the wheels sit flat on a smooth surface, etc.  Corrections to errors are easy as this point, but become much more involved once the boiler is in place. 




By now you have noticed a screw in the side of the block that has no apparent purpose (Part 1-17).  I haven’t the foggiest idea either.  The locomotive as it now sits has a number of the ubiquitous H3 hex headed bolts which fit the threads they mate to, but the nut driver provided in the kit doesn’t quite fit the head.  I went back to the old Aster red handled driver, and then tried a commercial driver with the same lack of luck – Aster has obviously found a vendor to produce these strange fasteners with an offbeat sized hex head.  If the application calls for an H3, which might need removal, and refastening after the locomotive is complete, I recommend that you obtain a quantity of the old H3’s from your Aster dealer and make a substitution.  One such place, which comes to mind, is the wick holder bracket.   




The assembly and installation of the axle pump box is as described, and the only fitting which is required is the filing out of the bypass handle to fit the stub of the valve. There is a fair amount of sealant being slathered about in this assembly, so you have to make sure that none of it gets in the wrong places. The pilot truck is almost intuitive in its ease of installation. 




The boiler is the most important part of a steam locomotive.  No part of this phase of construction is any less important that any other part, and some care should be taken to insure the integrity of the whole.  The instructions are quite decent at this juncture and the illustrations are excellent. With the successful air test of the engine, you will have the self-confident to tackle the job – just don’t rush it.   


One word of caution: the blower and regular valves can freeze in the closed position if you forget to open them at the end of a run.  If you try and unscrew these valves while they are frozen, the tubes (Part 5-6) will be loosened and will come out of the backhead.  If you use the red Loctite™ around the packing (Part 5-18) it will help keep the tubes in place.   


When you put the boiler bands in place, it will help you later on if you cement the N6 nuts to the band so that you can tighten the bands later on with the boiler in place on the frame.  The application of a bit of petroleum jelly to the B3 screws and then putting the screws in place will keep the cement from sticking the screw to the nut.  


The regulator and blower handles will have to be filed to fit.  Be sure and apply a good smear of jelly to all of the O-rings during the assembly of the boiler, particularly those small silicone ones on the regulator and blower steams (Part 5-PS2). 


While the smoke box is a separate section in the instructions, it should be treated as part of the boiler.  The design of the locomotive is somewhat less than optimum when it comes to this part of the assembly.  There will be space between the smoke box and the boiler jacket if the instructions are followed without some modification.  I took a small piece of the ceramic sheet and built a collar at the inside rear of the smoke box so that space was filled.  The sealant is used to hold this collar in place and it can be painted with the gloss black when it dries.  All air spaces should be filled with sealant to insure a strong draft.  


Mounting the boiler is a simple process but you’ll have to do a bit of fiddling to get everything bent and in place.  All of the cosmetic bits and pieces go on the locomotive at this time and you will really see it spring into shape.   


The side plates and fender running plates were supposed to be some sort of self-stick, but they were bare brass.  I fastened everything in place using GOOP adhesive. This is a good time to pressure test the system, and you can do this quite easily by running a tube from your air tank to the pressure gauge hole in the boiler.  The regulator should be able to control the speed of engine at this point – not too long running on air, remember. 




The burner in an alcohol-fueled locomotive is a critical partner in the success of the locomotive.  It appears to be simplicity in itself, but it is a subtle beast and you’ll have to get to know it to really understand its quirks.  First, the diagram in the instruction book is wrong – our locomotive does not have three wick tubes.  Other than this rather peculiar error, the information is correct.  


If the conservative approach of following the manual yields a good running locomotive, then you are through.  If not, you can experiment by reducing the number of wicks in each holder by one or two.  Most Jumbo owners have had luck with this set up. If problems with the fire still exist, Andrew Pullen suggests that you cut about 4 mm off each wick tube (concurrently shortening the wicks by the same amount and adding a 6mm plastic tube to the feed tube in the tank).  I did this to my locomotive and it really is a free runner.  You’ll have to build the tender before you can run the locomotive on steam, so let’s get at it. 




This is a very easy and relaxing assembly.  The tender sides are attached to the base when shipped and you need to take these apart before building the tender.  They are no tricky parts here, just be careful in keeping the sealant away from the pump ball.


You have just completed the locomotive, and what I recommend is that you polish away any fingerprints and just look at it for a few days before steam testing it.  The beauty of the small scale steam hobby is one of many faces – operating the locomotive is one of them, but just admiring the beautiful lines and colors is another.  The Victorian elegance of the Jumbo is a step back in time and the model will be one of your favorite possessions over the years.  




The instructions for the steaming of the locomotive are very clear, and there isn’t anything to add, except that I feel you are better off putting about 50cc of distilled water in the boiler and (partially) filling the alcohol tank about a third full for the initial test.  Be sure to fill the lubricator with steam oil! 


After the test run you’ll be able to see if there are any steam leaks (probably none), and then you can run it a few times to break-in all of the moving parts.  This is the time to experiment with the axle pump.  The pump is extremely efficient and will fill the boiler in just a few minutes.  My approach has been to just let the pump work against a partially shut valve so there is a dribble of water constantly being fed to the boiler. 

As you experiment you will find the optimum setting for the bypass. 


The break-in-period should be about two hours of intermittent running, and then you can put the Jumbo on the track for some serious revenue earning runs.  This is a deceptively powerful locomotive and it will need a load to pull if you want to hear the stack talk.  I’ve been running mine with a rake of five LNWR coaches built from Acme Engineering kits.  


There you have it.  The kit is a fine challenge for the beginning builder, and the result is a lovely runner.  Aster dealers will be a great help if you need a part of just some advice during the building of your Jumbo.  If you want some hand holding, please feel free to contact me and I’ll try to help you get going.


This article originally appeared in Issue No. 52 (Vol. 10. No. 4) of Steam in the Garden. Appreciation for permission to reproduce it on SouthernSteamTrains.com is expressed to Jerry Reshew, author; and to Ron Brown, Publisher / Editor of Steam in the Garden.


Return to Roster Page on the Jumbo




Home    ·    Reference   ·    Roster    ·    Photos    ·   Inventory    ·    Contact us    ·    Links