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Aster's Great Northern S-2


A review by Ross Schlabach



Following on the heels of the very successful Aster NKP Berkshire project, Aster’s reproduction of the Great Northern S-2 for the North American market takes Aster quality to the next level. This is Aster’s first Vanderbilt tender-equipped model, and their efforts have resulted in a unique locomotive that will be released late in April. Both Glacier Park (green) and black versions of the locomotive will be available with details, paint and numbering specific to certain engines. The bulk of the models – both kit and factory built – will be in the Glacier Park scheme which includes a green boiler, a graphite (silver) smoke box, and a red cab roof. There is a separate black version that is only being offered by pre-reservations received before the end of February 2008. The black version will have the same graphite smoke box but the cab roof will be black as is the remainder of that model. 

In order not to bore the reader, I won’t replay all the vital statistics of the Great Northern S-2 other than to say it is almost identical in size to the Berkshire. The S-2 has an extra pilot axle and larger drivers, so the locomotive portion is longer. But the Vanderbilt tender is shorter than the box tender on the Berkshire. The large drivers give the S-2 a taller and leaner look, and the drivers are fully equalized. Originally, they were to be solid gray iron castings. However, the prototype and production models feature "tires" made of iron, pressed onto forged brass center sections. This helps to keep costs under control; it has a main benefit of offering better traction than the stainless steel tires fitted on previous Aster models. This shows up in improved resistance to slippage – despite the larger driver diameter. The appearance and scale of the locomotive looks great in front of a string of heavyweight coaches, but it is equally at home on the point of a freight drag too. 

While most of the improvements and changes are “under the hood”, there are a couple of things live steamers may notice right off. This model is equipped with an operating headlight -- an LED bulb powered by a button battery for long life and simple operation. Also new to this model are a couple of changes to the gauge glass system. The glass and its supporting pipe system have been enlarged to improve the accuracy of water level readings; and the gauge glass is now fitted with a blow-down to ease the elimination of pesky bubbles. This blow-down also doubles as the blow-down for the entire boiler. 

Other not so visible changes include an improved C-type boiler with 3 flue tubes and simplified drain cock system. Not only is the drain cock system simplified from a construction standpoint, but it is very easy on steam pressure. And for those days when steam exhaust is most visible, the drain cock system gives off a very prototypical steam cloud – firing in sequence with the pistons left and right, front and back. The axle pump has been modified too. The pump stroke has been lengthened to 10mm from the 6mm stroke used on the Berkshire. This is to insure adequate water supply even as the S-2s larger drivers need fewer revolutions to cover each mile.  

Like the Berkshire, the S-2 cab was designed with RC installations in mind. There is a false back head backed by insulation to provide some protection against the heat. Both the blower and the regulator (throttle) protrude far enough back for manual operation; but servo arms can easily be attached to allow for RC operation. The reverser is positioned in the engineer’s side of the cab and looks like a miniature reproduction of a full-sized quadrant type with a ratchet detent system to hold the reverser in any position. It should be a simple matter to remove the mechanism and replace it with a servo to actuate the reverser rod directly – if desired. The cab controls also include a Berkshire-like whistle valve and the whistle body is mounted under the firebox shroud. The drain cock mechanism is not located inside the cab but below it. Under the right hand side of the cab, there is an actuator to control the operation of the very effective drain cocks, and the axle pump bypass wheel is just below the drain cock actuator.


The Vanderbilt tender is a work of art that hides some other handy modifications. As in the Berkshire, the S-2 tender has a removable alcohol tank and an easily operated, water tank drain. The design of the tender is such that there is plenty of room for RC gear & batteries, and there is a hole below the footplate for servo leads to pass. Some may think that the clean lines of the tender means that something is missing, but not so. This engine had a fully-welded tender, so there are no rivets by design.  

Another special treat on this tender will be the inclusion of real wood planking on the rear deck – above the water tank. The prototype models displayed at Diamondhead did not have this but we’ve been assured that the finished models will. For those of you who are familiar with the Aster Big Boy, the wood decking on the S-2 tender will be very similar to the wood decking on the Big Boy model. This detail should add a dramatic visual impact to the model.  

Firing up the S-2 is simple – and quick. “Oiling around” is accompanied by filling the displacement lubricator on the left running board, and adding alcohol/water. Once the boiler is half full and the wicks have had enough time to get saturated, the burners can be easily lit using the fire door in the cab. With the external blower going, the S-2 builds pressure quickly. At 2 bars, the blower can be removed and the engine transitioned to internal steam blower operation; and 4 bars pressure is reached in a total of less than 5 minutes! (Average running time on one alcohol fill is an impressive 50-60 minutes.) 

Select your direction on the Johnson bar, open the drain cocks, and ease the throttle open. You are rewarded with a nice sequence of steam exhaust as the drain cocks clear the condensate and signal the alternating blasts of high pressure steam. Surprisingly, this locomotive makes so much steam that the drain cocks can be left open during mainline operation with a solid string of cars, and the engine can still pop-off! The engine tracks extremely well with no noticeable “waddle” to its movement. In operation, I found the S-2 every bit the equal of the famous Aster Daylight. Traction is excellent and the S-2 provides drawbar pull unexpected on such a large driver model. 

For the majority of folks who will be assembling their S-2s from kits, the instructions will be in the classic Aster format with isometric drawings and separate, detailed, step-by-step directions.

With the Great Northern S-2, Aster and its North American importer, Hans Huwyler, have developed an excellent model with new features and even better operation than the fine Aster models of the past. This is a model that Aster customers will be able to build and run proudly for many years to come. 


This article originally appeared in Issue No. 98  (Vol. 18. No. 2) of Steam in the Garden. Appreciation for permission to reproduce it on SouthernSteamTrains.com is expressed to Ross Schlabach, author; and to Ron Brown, Publisher / Editor of Steam in the Garden.




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