Two weeks ago the Trains and Locomotives program on RFD-TV did a feature on the museum at Dennison, Ohio. The local model railroaders have built a layout in the depot which houses the museum and is representative of the Dennison Division Point as it existed in the old PRR days.
There were two turntables and roundhouses represented on this layout; I am certain this was prototypical but no explanation was given as to the reason for the second turntable/roundhouse. It is possible, I suppose, that the volume of traffic through this point increased to the point that a second turntable/roundhouse became necessary. I am equally certain, however, that another potential reason may have been that, as the length of locomotives increased, Pennsy may simply have run out of lead to their first roundhouse allowing for the expansion of the turntable.
If one looks at a roundhouse and sees different lengths of bays then a logical conclusion to be drawn is that that roundhouse has been expanded to fit a longer series of locomotives and the turntable, therefore, has been increased in diameter for the same reason.
My question is this: assuming enough lead to allow an expansion of the turntable from, say, 90 feet to 120 feet, how did the railroad company expand their roundhouse to fit their longer locomotives? Specifically, did the company create longer bays by extending to the back of their existing structure? and if so, how might this have effected any backshop buildings? One of the (model) roundhouses cited previously showed a variation in bay length but, if I recall right, these longer bays were off to one side; this may have minimized interference with the backshop. Is it possible that, rather than extending the length of the existing bays, the company would have constructed new bays at one end of an already existing structure?
Kalmbach’s The Model Railroader’s Guide to Locomotive Servicing Terminals may well cove
Adding longer stalls to the side(s) of the roundhouse.
Building a separate roundhouse with longer stalls.
Building a separate (usually rectangular) enginehouse, not necessarily directly connected with the turntable, for the longer locomotives, such as the “Mallet houses” the Southern Pacific built in such places as Dunsmuir and Truckee, California yards.
Not adding to or modifying the roundhouse, but just letting part of the tender stick out, like at SP’s Port Costa, California engine terminal.
While we’re talking SP here, they set great examples for the types of questions asked here.
SP commonly had “freight” and “passenger” roundhouses, such as Bayshore (freight) and Mission Bay (San Francisco) with the latter being built in much closer proximity to the passenger station than the former. Alhambra Street (passenger) and Taylor(freight) in Los Angeles were other such examples.
Expansion of roundhouses was done by either adding stalls of greater length, expanding the existing stalls out the backside of the roundhouse or by creating run through tracks. SP’s cab forwards often rated “Mallet Sheds” such as at Dunsmuir, due to their considerable length. Roundhosues modified to accept the big AC’s often had Mallet Tracks and Mallet getaways to accomodate the larger articulateds.
In many places the “backshop” was a completely separate building not connected to the roundhouse. The roundhouse was for running repairs, a backshop was a building for doing heavy repairs to an engine. If you wanted to replace a flue or work on the valve gear you did that in the roundhouse. If you needed to rebuild the boiler or change out the drivers, you did that in a backshop.
A roundhouse is like going to your doctor’s office for a checkup. A backshop is like going to a hospital for surgery.
Union Pacific’s Cheyenne roundhouse was two parts, as mentioned before they had what were referred to as the Passenger House and the freight house. The two houses were separate but serviced by the same turntable, and totalled 48 stalls IIRC, which was not quite but close to a full circle. the freight house had direct backshop access through 5 of its stalls.
I believe, but could be wrong on this point, but the original turntable was long enough to handle both classes of Challengers. IIRC, the stalls had to lenghtened out the back to accommodate them. When UP ordered the Big Boys they installed 130’ turntables at several locations including Cheyenne. To be able to close the stall doors (it gets REALLY COLD in Cheyenne in the winter [swg]) they extended some stalls 11 feet as I recall, towards the turntable, as extending further out the back was impractical. In Cheyenne, they lengthened both directions to fit the BBs, so a RR could extend either direction, which ever was most practical in each scenario, or as also mentioned earlier adding longer stalls to one end or the other would often be the easiest rework.
Is everybody ready? Here comes my stupid question of the day!
Considering some of my previous posted responses one could come to the conclusion that I am anti-Big Boy! Such is far from the truth, however; I am, admittedly, not a rabid Big Boy-fan, maybe, when it is said and done, because I grew up in UP country - eastern Idaho - and, therefore, UP is not my favorite railroad.
The Big Boy is, perhaps, the most mythologically shrouded (steam) locomotive that has ever been built and this mythology even begins with its service i.e. the locomotive was not designed for operation over Sherman Hill but across the Wasatch; it didn’t move into the latter service until the late-‘40’s-early ‘50’s flood of diesels bumped them eastward. Admittedly this locomotive’s longer length was going to require some adjustment to the railroad’s physical plant but why, pray tell, would Onion Specific have wanted to build a 130’ turntable to accomodate a locomotive that only scaled out to a length of 129’ 9 1/2" over the engine-tender pulling faces and only had a 116’ 6 3/4" wheelbase from the lead axle of the pilot truck to the rear axle of the tender? It seems to me that a 120’ turntable would have been sufficient for turning this turkey: I do seem to remember reading somewhere, however, that before they could be put into service over Sherman Hill the turntable at Laramie was expanded to about 126’. An expanded turntable at Cheyenne was unnecessary, I believe, because of the wye located just west of town. I know they probably exist but I don’t recall ever having seen a photograph of a Big Boy on the Cheyenne turntable - Laramie, yes! Cheyenne no!
Considering their commitment to dieselization when the Onion Specific moved the Big Boys out of the Wasatch to Sherman Hill I wonder just how much additional service they expected to get out of these locomotives; compared to the purchase price of replacement diese
This double roundhouse thing isn’t unique to the west… B&O had dual roundhouses at Riverside Yard in Baltimore, which I believe survived into the 1970’s, and a pair at Martinsburg, WV that still stand… one is now a community events center, and the other is an historic ruin, but they’re there… These date to the earliest days of the railroad in that area.
Enola Yard near Harrisburg, PA also sported twin roundhouses used by the PRR. Only one turntable survives, but it gets regular use as part of the busy engine terminal there.
Dave, the B-B+B-B units - 51-75 - were 84’ 7 1/2" long; I don’t have figures on the big C-C truck units - the 8500 HP 3-unit monsters - but I’m quite sure that they would have been too big to have fit any turntable in place. I suppose that if circumstances required turning on a turntable they could have been broken apart and hostled onto and off of the table with a conventional switcher then reassembled and restarted.
There were wyes at both ends of where these unit’s ran - at Council Bluffs and Ogden.
A sidebar:
In the 1960s, while on a PCS move with the Air Force I had occasion to travel across southern Wyoming and southern Nebraska on US30 twice, once eastbound and once westbound, and I encountered these turbines four - perhaps five times - in the course of these travels.
In July of 1964 I was headed to Taxachusetts for what would become the second worst assignment of my Air Force career; I had had dinner at what used to be my favorite eating location, the Virginian Hotel in Medicine Bow, Wyoming. I was getting the family back into the car to resume my travels eastward when I heard the most god-awful roar and looked up to see one of these 8500 HPers and a couple of Geeps with a westbound freight. That turbine was really wound up and whining with at least a hundred cars in tow.
About an hour and a half later I’m on US287 just south of Laramie and I looked off to the east and there was another westbound just coming down off of Sherman with what appeared to be another of those 8500 HPers on the head-end; the distance at that point, however, kept me from making a positive identification and this is my possible sighting.
After a short visit with in-laws in Colorado about a week later I’m on US30 in Nebraska just east of the Wyoming line and I looked in my rearview mir
As far as two roundhouses / turntables, although there were some ‘full circle’ roundhouses out there with around 60-70 stalls, in reality that could become a major bottleneck since only one engine can be on the turntable at a time. If a railroad needed stalls for more than 35-40+ engines at one location, it usually meant it was a pretty busy location, and in the long term it was more time- and cost-effective to build two separate roundhouses and turntables.
Believe it or not there have been fully covered roundhouse/turntable complexes and I believe it was RMC, in response to an inquiry, published an aerial photograph of one - I don’t remember where this facility was located.
On another occasion Craftsman, in response to an “Are roundhouses ever completely round?” inquiry, published an aerial photograph of a two roundhouse/two turntable facility - if memory serves me it was located in the proximity of Pittsburg on either the P&LE or P&WV. One of the roundhouses in this photograph covered close to a three hundred and sixty degree arc - the turntable access track, of course, kept it from being a “full circle” - and it had a very short lead from edge-of-pit to roundhouse doors - it is hindsight because I didn’t really think of it at that time but as I recall this particular photograph I have a feeling that this turntable itself had been expanded and that accounts for the short leads. One of these days I’ll run into this photograph while browsing and one of the things I’m going to look for is going to be indications of how it may have been expanded.
The second roundhouse only occupied an arc less than one hundred and eighty degrees - say one hundred forty to one hundred sixty degrees - it had considerably longer pit-to-door leads indicating, to me, that it was newer and had been purpose-built to house longer locomotives; even at that time I got the feel