Typical Plans & Sketches

Typical Examples



32.0 TURNTABLE Last Revised: September 23, 2004


Turntables were once a very common railroad installation in Indiana, however with only a few exceptions, nearly all have been removed and none have been preserved in operating condition. This turntable will be the centerpiece of the museum plan with tracks radiating out from the table on all sides. Some of these tracks will eventually lead into a planned replica roundhouse structure (#33.0), built at a later date. The turntable saved by the railroad is approximately 84í long and was built circa 1920. It is of the most typical design used. The functional design of the table is that it is much like any moveable bridge, except that it requires suitable abutments / retaining walls on all sides. The retaining wall and a heavy center bearing support are constructed with poured in place concrete. The construction of the pit wall and support bearings is therefore crucial to the reinstallation of the historic steel table structure.

Turntables were required due to the basic design of a steam locomotive to have a distinct forward end that had to be redirected (turned) at the end of each run. Turntables were designed to be a convenient and space efficient way to do this and were often part of an engine terminal that included the form following function roundhouse. These were both once very common structures. Connersville, for example, once had two such turntables built by two different railroads. When diesel locomotives became the standard, hundreds of turntables were removed with four known to remain in place today in Indiana, though these are not open to the public.

This table will help interpret the role and function of these large moveable structures once common in the railroad industry. Key concept would be to highlight the reasons a turntable exists, essentially related to steam locomotives. The second part of that story is how the diesel era allowed for bi directional locomotives, though not at first, followed by the elimination of turntables. This table will be used to place equipment on display in efficiently grouped tracks while providing for the ability to turn equipment. Operational equipment will use this facility and will be viewable by visitors at certain times of the day.

The relationship of the turntable to the roundhouse is basically about locomotive maintenance and readiness. Steam locomotives were used by the railroads until the ascendance of diesel engines in the early 1950ís and worked side by side until approximately 1957 in Indiana. Steam engines are by design uni-directional and require turning when they are to travel long distances in reverse.

The turntable is a large steel bridge that rides on a center bearing with rollers at each end that ride on a curved rail. The turntable bridge sits below grade in a pit designed to hold the table. An operatorís control shanty is located along one end of the bridge where they control not only the table movement, but lock it into place when the desired track is reached. The shanty is not much more than a protection shed for the electric motor controller.

Interpretation Methods:

Primarily through the display of the table with other written wall mounted information on or in the control shanty. Periodic turntable rides are not out of the question and may be incorporated into a public tour at some point.

General Structure Design:

The only solution is to build a replica turntable pit structure that would fit the turntable and track design of this site. An exact replica pit is probably not entirely possibility as proper photos and full documentation of the old table were not kept when the turntable was removed from Newark, Ohio. The key to the success of this project is that the table remains level and operable for many, many years to come. Tables that do not have proper foundations can become out of level and are of little use. One of the benefits of this tables outer ring rail style is that it less likely to have this occur as compared with earlier fully balanced designs. The center pier top in the original installation was a block of granite with a smooth top. This material was used as it could create a perfectly level surface. It may be possible to use concrete designed for precision machine tool pads. Alternatively, a large block of stone could be used again. The floor of the pit should be fully lined with either brick or concrete. An access pit should be placed at some point around the edge of the circle near the ring rail. The purpose of this pit depression is for an individual to be able to access the electric motor and bearings for lubrication and servicing. Another sump should be added towards the bottom of the "bowl" near the center bearing for a electric sump pump installation. A discharge pipe could be built into the pit floor with the discharge being directed to the ditch along the south edge of the property.

The bridge structure itself is of riveted construction and in good overall condition. The steel has little of its original paint and will need to be repainted. The rollers will need to be cleaned of old grease and scale and lubricated before they are installed. The table is presently located some distance from the display site and will have to be moved by rail back to Connersville on our railroad. While the turntable bridge is made of steel, the deck of the bridge is wood. Specifically it uses wood bridge ties that will have to be dapped (routed) to match the indentations of the beams, rivets, and joints. These will have to be made to order as our bridge decks were in past years. The table will need about 70 ties. With this tie order, we must also order the handrails for the table so that they can be fitted with the deck material by the wood supplier. It is not known if the tie attachment hardware from the original can be reused or not. The original ties from the table are apparently in storage and they can be used to determine the dapping pattern. The rest of the deck located in between the rails and to the outside of the rails should be filled in with planks. These should also be ordered with the deck materials if at all possible.

Electrical service to this structure will be required, though it is not known to what magnitude. It is believed to be three phase 240 volts, though it may be 480 volts. The electric motor for the table should be sent out for cleaning and testing prior to installation. The control cabinet will also need cleaning and testing. An electric pole will need to be located outside the pit wall edge at some location, likely to the west or north, so that power lines can cross the pit and travel to the pickup shoe device located above the center of the turntable bridge. The contact shoe allows the table to rotate without interruption to the power supply. It rides upon a trellis type support that spans the track at the center of the table. This support is made of wood and is attached to the handrail and deck assembly. It is not known at this time if the original support assembly is available as a direct pattern or if one will have to be designed.

Rail for the bridge deck should extend, in as much as possible, to the maximum length of the bridge deck and overhang by a few inches. A small gap is left between the table rail and the rails on the concrete ring. A locking mechanism for the table end should be designed and fabricated if the original is no longer available. The operatorís shanty should be located next to the locking mechanism on the end of the table. Remains of the original shanty exist. It is approximately 4í x 4í in size. It has a single hinged door and a window on each side.

Structure Usage:

Beyond general interpretive use, this structure could serve its original function to turn equipment being stored in the roundhouse and surrounding tracks.

Priority Level in Museum Site / General Structure Complexity:

High / High

Special Location Considerations:

The table needs to be far enough to the east to allow for full usage of the property while not compromising the design of the roundhouse and ramp area as well as the power house and east parking lot area.

Supporting Artifacts Available:

The turntable bridge, electric motor, control equipment, curved pit rail and other small parts are on hand.

Supporting Artifacts that would need to be acquired:

It is not yet clear which items would still need to be acquired.

The Whitewater Valley Railroad is a 501 ( C ) 3 not for profit operating railroad museum dedicated to the preservation of a historic branch line railroad, to the restoration of railroad equipment, and to the conduct of educational railroad programs.