Thursday, 5 March 2015

CPR 70' HALF DECK TURNTABLE

Having received a few questions and comments about our latest project, the Turntable and Roundhouse in Brookmere, we will give a detailed response here and publish plans and photos of the prototype and some details on our miniature interpretation of same.

In operating a model railroad, it becomes quickly evident why the prototype built these items because a method of turning steam locomotives is a vital necessity.  The two most common methods for turning engines were the Turntable and the Wye.  Sometimes a loop track was built and employed, an example of the latter being the loop at Princeton but these took up a lot of real estate so were rarely the preferred option.  Incidentally, larger KV locomotives were restricted in their use of the loop track in Princeton which was a very tight 15 degrees of curvature.

It is evident that the 70 FT HALF DECK TURNTABLE was a fairly standard type for the CPR. The seventy footer was to be found at several locations along the southern mainline according to photographic evidence and documents in our collection.  At least one is still in existence today in Victoria BC.  On the southern mainline there were possibly ten located between Medicine Hat and Odlum.  On the Kettle Valley Division, 70 foot Turntables were located at Brookmere, Allenby and Copper Mountain.  This size was adequate for most steamers at the time of installation in the early part of the 20th century.  But the P-1n class locomotives with the larger tenders coming on stream in the late 40's, were too long to be turned on them.  This became a moot point as the larger engines generally were run between the major terminals which were equipped with larger tables.  Shortly afterward, dieselization took place and the need for this device diminished.

The focus of our study today is the 70 foot turntable at Brookmere which served the railway well from 1915 until the passing of the steam locomotives.  Here is a shot by my friend, the late Glenn Lawrence taken in 1954, shortly after dieselization.  [Update:  This is a clearer picture that has come my way from a mutual friend of Glenn's]


A few details to note here.  The exterior engine storage track to the north of the engine-house has been removed but only recently.   This track shows on the drawing from 1953 and in a photo from 1952.  This is the only shot we have showing the drive motor from this, the exterior side.  More about this later.  The overhead piping to supply the air for the drive motor is cut off by the photo edge.  The piping ran over to the pump house.  Before the erection of the pump house at the time of the Bunker "C" Oil facilities, the table was powered by means of the engine air supply which was fed through the hoses seen on the deck in the foreground.  Hoses were also fitted at the other end, hence the pipe that runs the length of the turntable.  Part of this pipe was removed sometime later as it does not appear in the Lawrence photo published in a previous post and herewith presented again. 

 The pole to the right (or east) of the pit in both photos has a cable running to another pole on the opposite side of the pit.  This cable supports the air line which, as we said, was run to the pump house.  I suspect it ran down the post and went underground from there.  The drive motor appears in a photo from 1944 but of its existence earlier than that we cannot say.
 

Here is a Lawrence photo taken on the 1968 trip.  Extraneous marks appear in the original. Unfortunately, there do not appear to be measurements or drawings of it.  Hal Riegger published a good photo of it on page 216 of his book, The Kettle Valley and its Railways.  The Victoria turntable drive motor is quite different.






This photo is a recent acquisition and was taken by a fellow KVR modeler when it was lying discarded in the pit many years ago.  Apparently it has disappeared since.  At some point - probably 1970 or so - the bridge was cut up for scrap, leaving the pedestal and the centre core of the bridge which still sits there to this day (on private property).  As can be seen, there is a great deal of gear reduction designed into the drive mechanism.  The interior sprocket is paired up with the drive wheel the flange of which is seen projecting slightly past the teeth.  The bracket seen on the left was bolted to the girder side of the Turntable.

Another shot which may be of interest to the modeler, is this one of a section of the turntable pit taken in the 1980's.  
The gap in the upper concrete rim is the opening for the "coping timbers" on which the rails were placed.  They functioned as cross ties in stead of the rails sitting directly on the concrete.  The rails in this location were the turntable leads on the west end of the pit.  It would seem that the pit rail was shimmed with the many wood wedges pictured to get it true to the table and the drive wheel.  The vertical lines on the inner wall are rust stains caused by rain water running off the gullies in the horizontal part of the pit wall.


Here is another shot by Glenn Lawrence showing detail of the bridge deck which is useful for modeling purposes.  The exposure has been lightened up to better provide detail.  Note the pole to the right (or west) in the photo which supports the air pipe previously mentioned.







Another photo of interest is one to be found in J. F. Garden's book, The Crow and the Kettle.  On page 37 is shot of a C-Liner posed on the turntable at Crowsnest.  The rails of the table are higher than those of the leads and this was standard practice.  Refer to the drawing below which specifies a 1" difference.  The need for this was seen in a movie of a CNR locomotive edging on to a turntable with the result that the table very definitely sagged under the weight of the locomotive as the Drivers contacted the bridge rails.  This would not be a design feature for model builders to adopt.

Finally, we present a CPR drawing of the turntable and pit with all the detail necessary to build one in scale or full size even!

The drawing was made by a gentleman, initials "MG" who published various other drawings in the 1985.  I bought a set when first released and have not heard of him since.  Efforts to trace him or his company, Mainline Design Group, have been fruitless.  I truly hope that he is agreeable to my publishing this rendition of his drawing.  This is a not-for-profit Blog site and our motivation is to further the hobby and help modelers with accurate information for their building purposes.  I have no interest in collecting stuff, just to "have it".  Or in making money off a hobby.  The original was drawn up 100 years ago and I doubt that a copy of an original falls within copyright laws since it is in fact, a copy - albeit, a beautifully rendered one.

For some additional photos of another CPR 70 foot turntable check out the one that was located in Goderich Ontario: http://www.trainweb.org/oldtimetrains/CPR_London/goderich_turntable.htm

Next post will be a description of how we built a model of the Brookmere Turntable.

Coquihalla Man

2 comments:

  1. Suddenly feeling a little queasy at the thought of trying to model this in a not half-a---ed way in n-scale. It is amazing how many key details there are. So grateful that you have taken time to educate and share. It will be years before I get to modelling Brookmere.. but this is very helpful.

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