A question for any and all turntable experts out there,

Should the radial tracks be level or have some gradiant (either towrds the pit or towards the roundhose) to them?

Are there advantages or disadvantages towards either design?

(I have my own suspicions, but I need some more info to prove or disprove them.)

Thanks

Jason Midyette

Hi Jason,

As a civil engineer with no experience in turntables, I would hazard the opinion that ASUMMING that turntable pit is properly drained, to keep water away from the roundhouse. maybe 1/2% down from the roundhouse to the pit.

Doug vV

I don't have any experience with turntables and roundhouses, but as a thought, I wonder if a slight grade leading up to the turntable might form a last line of defense against cars and engines rolling into the pit by accident.

[quote="6-ET" . . . I wonder if a slight grade leading up to the turntable might form a last line of defense against cars and engines rolling into the pit by accident.[/quote]

Definitely. That way you can kick em out the back wall of the barn instead. ;) Pick your poison, I guess.

Having a level grade to a turntable a must, but grading down away may help prevent an errant mistake and rolling in the pit.

recall some western turntables were above ground because the rock ground to tough to pit down, so you had a grade up to the turntable.

You have to release your brakes and nudge power to/from the turntable, upon release I don't think you want to be prerolling any direction. It may save on any crazy throttle/brake nudging having a level entry.

Level unless there's a damn good reason not to have it that way.

I would have to agree that level is the best and safest way. My only experience with turntables was at the D&S in Durango for several years as a hostler and engine watchman. From what I could tell, all tracks were level from inside the roundhouse all the way to the turntable pit. Some tracks had a low joint or a "Dutchman" track repair about halfway (intentional or not) that would tend to slightly trap whatever rolled through. You just had to work a little more steam to get past that point, in either direction. My experiences at the CO RR Museum also indicate that all tracks are level to the turntable.

My 2 Cents

Mike Ramsey

At the Connecticut Eastern Railroad museum the rail grade is a 1"-2" drop (IIRC) from the pit to the front of the roundhouse and then it is level across the pits. This is to prevent a photo #2. Distance from pit wall to Roundhouse front wall is ~45'. Since the Roundhouse area sits on 15-20 feet of sand & clinker, ground grade was of minimal concern, but a ~1/4% grade would really have minimal impact on drainage unless you are talking Concrete or Hardpan. Add to that the turntable & roundhouse pits were pre-existing (built 1892), we could only do so much to make sure equipment didn't roll out of the roundhouse.

Not sure with photo #2, but I know with photo #1, that happened at the Hartford Roundhouse in 1904, and from what I have been told, the reason #231 went through the back wall was she was a `Night Walker', where due to the construction of the boiler, as the boiler cooled the boiler shell shrank at a different rate than the throttle rod and in doing so opened the throttle valve a hair, thus allowing steam into the cylinders. This allowed her to create enough momentum to blow through the rear wall of the roundhouse. This is why it became standard procedure to install chocks or drop a chain immediately in front and behind a main drivewheel when a steam locomotive was parked to cool. The valve doesn't open enough to allow the locomotive enough energy to climb over the chock or chain but if they were allowed to roll a few feet a brick wall or wooden door wouldn't stop the momentum. IIRC the solution was to run the throttle rod through the boiler so everything was at the same temperature and thus cooled and shrank at the same rate, but I could have it backwards and the exposed throttle rod was the solution.

Rich C.

Level all the way. From a safety standpoint, you don't want equipment rolling into the pit or into the house. Both are bad, but the house would be more likely to involve human casualties to workmen. While most radial tracks don't have room to store large equipment between house and pit, particularly if you're using all the stalls all the time, if you do put something there you don't want it to roll either direction. From a logical standpoint, add the fact that any incline would require additional force (throttle) to get an engine up onto the table or up into the house. That alone requires a much greater degree of finesse in a confined operating space with the added requirement of precise stopping. Better to not have to goose it.

Also to consider if you're designing new - some houses had bumping blocks at end of track to keep things from knocking down walls. That would add some justification if you really want to drop grade from table to house, but adds other concerns like floor obstruction, pinching hazards, shorter usable track length, and expense.

The runaways in the photos above are usually the result of moving engines without adequate air for brakes or leaking throttle/valves. Steamers were often hostled on banked/dropped fires when there was enough steam to move the engine but not enough to run the air compressor, and will move with very little pressure in the cylinders, so that was/is the bigger problem. Always use chains or chocks around the house/pit.

Anyone who's worried about drainage should be looking to grade the ground, not the tracks. There are many examples of different drainage techniques around roundhouses. You can grade surface away from, install drain tiles/covered sluices subsurface in front of the door wall, etc., and the pit definitely needs a working drain (with oil skimmer nowadays) unless it's a dirt pit with an open side.

As level as possible.

Heartily agree with those who have stated this before me.

Fourth Edition-1939 Railway Engineering and Maintenance Cyclopedia page 598 refers to A.R.E.A Standard Practice relative to the design of new engine houses.

5. Tracks. (a) Lead tracks to the turntable should line up with tracks of the engine house or opposite radial tracks.
(b) Engine house tracks should be on a level grade and should be provided with stop blocks or stop pits.
(c) Special fastenings of the track rails at the circle wall and on the turntable are desirable to prevent movement of the rails, to give good bearing, maintain gage, and to lessen the damage from derailed wheels.

10. Floors. The floors should be of substantial construction and sloped so as to afford proper drainage.

TrainDetainer, Any operator that is not able to drag brakes and proceed at a pace close to or slower than a slow walk, has no reason to drive equipment into a building (either due to operator ability or equipment condition). The incline we have is shallow enough that while dragging brakes and running 1 engine, at idle, our 44 tonner enters and exits the roundhouse safely with the ability to stop in under a foot. The 25 tonner and the Railbus neither have to go above idle to leave the roundhouse, all self-propelled equipment must drag their brakes for safety, as you don't have the luxury of time to remove the slack in the brake rigging.

The grade we have is gentle enough that, while I am not the biggest bull in the china shop, I can push our Fairmont 3100 Railbus (MEC 10) or our RMC Spot Tamper out of the roundhouse and onto the table by myself. The incline will mildly accelerate equipment coming off the table, but not enough to do more than a good thump against similar weight equipment, over run a rail stop (clamped or bolted) or slide a wheel skate more than a foot (under a heavy car running from the table to the end of the 60' pit), but anyone knowing about the incline should always make sure provisions were made to eliminate as many possibilities of a runaway over the short distance we are talking about.

There is no reason for someone to stand at the end of a shop rail or between equipment, while equipment is moving towards them, in case of a misstep by them or the operator. When moving equipment in or out of the roundhouse nobody other than the assigned brakeman is allowed in the adjacent bays, and the brakeman always stays between the active and adjacent pit on the engineer's side, and always in view of the engineer, while directing them to the stopping point or onto the table. If the brakeman has to go around something, all movement stops until they are back in view.

With photo #2 (Hartford Roundhouse), that era of steam locomotives rarely had hand or air brakes installed on the locomotive, which is why there are so many cases of night walkers exiting the roundhouse when no one was around, up to the turn of the century. All they had was the `steam brake' of moving the Johnson bar just past neutral, thus lightly reversing the steam flow into the cylinders to counter the motion of the locomotive.

Rich C.

Rich -


I'm glad all your operators are top-notch qualified and your equipment is in perfect working order at all times so that things always go smoothly and without incident. Most places aren't so lucky. I'm bored at the moment, so neither are you.

Seriously, Jason's question is about design. When we design a thing, whether it's a complete system or just a single piece of hardware, we have to consider what happens when things aren't perfect. 'Accidents' don't happen when everything is up-and-up. They happen when the junior engineer at the museum is the only one available to move the old 44-tonner with the bad independent out of the way of the day's excursion engine at the last minute and the only place to put it is on bay 5's lead while the guys have the sawhorses propping up some new car parts for welding inside the house with the doors shut against the cold. And they're working in bay 5 because that's the bay with no pit and it's empty. See where I'm going with this?

The most advantage has to be given to minimizing hazards, by and during design, so by not adding the goose factor to the equation, maybe the guys with their heads down while they weld won't have to feel the the one that got goosed without full control coming through the doors.

And even if everything is 'perfect' with crews and equipment, immediate unpredicted failures are always in the equation. Just one of many examples - on a heavy coal train in somewhat cold weather - I twice stopped the train with air, ran around it and re-inspected/tested and ran a full running test enroute to the hill and everything worked as expected. No problems whatsoever at any point. Good power, no kickers, good braking effort at every reduction, plenty of recharge time. But when I started over the top of the long, steep, twisty hill and pulled the first twelve pounds off, I might as well have asked for the moon. Nothing. Had to change my plan and shoved the dynamic handle all the way forward. For those of you who need the rest of the story - Eventually dumped the air (no power knock-out on that unit) and glued my eyes to the speed indicator to see if we were still accelerating or under control. Conductor asked if he should jump, I talked him out of it. Needless to say I'm still here and we made it to the bottom without further incident. Luckily that hill levels gradually near the bottom and I could release/recharge when we got to the point the dynamics alone could handle the train, and I'd got up enough air to stop at the yard almost like nothing had happened.

So, does that junior engineer with even a good brake valve need the added challenge of a goose-it situation on top of everything else? Should I have had to take that train on that territory if one or more dynamics had been reported defective, or not equipped? We design for what's generally known as the lowest common denominator - that's the safest course. Reduce the possibilities for failure. Every 'accident' is a chain of events with each link a contributing factor. The 'accident' can usually be prevented by breaking a single link in the chain, so why add links to the chain?


I hope your operators or anyone who might have to push the railbus on the incline is required to read RYPN before hand.


You're right, there isn't under the circumstance you pointed out. But what about those guys in bay 5 with their heads down and the welder going and the doors closed? And what about the visitor who shouldn't be there or the worker who, for no apparent reason, walked across the bay at the last second? One yard I worked in a brakeman with 30+ years in and a good record didn't come in for break after kicking the last couple cars into the yard. Conductor and engineer went looking for him a few minutes later after he should have come in. They found both pieces of Bill on track 5 - apparently he'd gone to open a knuckle as the car rolled in, but we'll never know if he was opening one on the fly or what happened. But the rules say he shouldn't have been there, and he was trying to do a good job as always, so ????

Hi,

Why worry about little items such as turntable pits and round houses? <GRIN>

FWIW, this installation is at the end of the Monarch Branch and all they needed was to turn locos.

Doug vV

This is seriously drifting off the design aspects, If you actually read what I said, the grade we have is so low that to come out of the roundhouse safely, brakes have to be drug, as all the equipment when operational, have more than enough power to roll out at idle only, no Goosing needed. In confined ares, no matter if you are in a roundhouse, engine shed, storage building, near the station or in a tight yard, there is no reason from a safety point of view to go any faster than a walking pace, and most self propelled equipment, unless held back by dragging brakes will be at a trot in no time. If you are coasting in these areas, you are not ready to safely stop.

-----
As far as the aspersions thrown back at me. I guess you are not reading what I am writing, I am saying all possible precautions should be taken when moving equipment in and out of the building, it doesn't matter if it is uphill, downhill or flat to the roundhouse. Yes there are things called accidents, no one as made a working crystal ball that accurately sees the future, but our jobs as operators are to remove as many possibilities in creating one as possible. Thus if you are moving something with bad brakes into the roundhouse, you either tether/couple it to something else that works, to prevent a runaway, or you use a wheel skate (or a timber) that is tied to a rope, so the skate can be pulled safely down the track and kept a foot or two in front of the wheels by a second brakeman or assistant. I mentioned being able to hand push the lighter equipment to show how mild the grade is, and only for that reason.

Wheel skate, for those that are unfamiliar with them, are designed so that if you over run one the wheel hits the chock area, and the skate slides on the track, to bleed off the inertia with a larger friction surface, as compared to just a chock that could be kicked off the track or run over.


I don't know about other museums, that operate equipment around the general public, but one of the first things that must be taught to any operator (after starting, stopping, operation, & emergency procedures), especially before they operate around the public or in confined areas, is how to maintain control of the equipment and to feather the brakes. Maybe we are also odd in that we train and clear people on a per piece of equipment basis and not in equipment in general (as each piece tends to react slightly differently in starting and stopping forces and reaction times).

If we are testing equipment after a repair, (and after stationary testing has been successful) the locomotive is pulled out with another locomotive (usually the Trackmobile as it is the smallest and operates like an automobile [i.e. easiest to train a junior operator on...] ), that we know is running correctly and brought out to an open area of track where there is room to test and over run imaginary stop points, the same thing is done when training/recertifying an operator, a place is chosen next to the track and the operator/trainee learns to stop softly in the correct spot where if they over-run the mark nothing gets damaged (i.e. stop as if that bush next to the track was the platform..., or that stick stuck in the ground is the near corner, or coupler, of the car you are coupling up to...)

As far as running into an occupied bay with `Welders with their heads down', that should never be allowed to happen, just like how Home Depot, Lowes, Costco, BJs, etc..., close the active and adjacent lane when a fork lift is pulling a pallet from an upper shelf, work stops and people are cleared from a work area if a piece of equipment is brought into that work area. Their procedures were not created to inconvenience employees or customers, but to keep them safe so the same should be done by Us (I mean anyone around heavy equipment, especially temperamental old & antique equipment). Remember OSHA rules and procedures apply to us also (operating non-profit museums). Since we are talking about the distance from a table to the roundhouse (45-100 feet) there is no reason to run equipment off the table up to a closed door with people working behind it, if you need to park something outside the door, then everyone working in that bay takes a 5 minute brake till the locomotive is parked. Inconvenience is BS, Safety of personnel is paramount.

With the comment about John Q Public being where they shouldn't,
.....A. When you see them, you stop immediately until they are out of the danger zone
.....B. You should always be operating as if there might be someone hidden (which is why you should always drag the brakes in a confined area, so you can stop quicker).

Basically In summery, It is our responsibility to do as much as possible to make sure everyone goes home in one piece and unscathed at the end of the day and to make sure our equipment is always right side up.

Other than further discussions on track slope, this is the end of what I am going to say on this topic in the open forum.

Rich C.