Tuesday, December 18, 2012

This Float's For You, Part Deux (or, "So you still want to know more, huh?")

      Well, hopefully, you’ve come back to read a little more. Hopefully by now, Riley has read Part 1, and is anxiously awaiting Part 2, or so I can hope. In this installment, we’ll be covering the locking “mechanisim” I built to lock the floats in place, and also the operation of the float bridges themselves.

       So like I said, we left off at the carfloat and their cart at the float bridges, so now let’s take a  look-see at the "how do I lock 'em in" question. I needed something robust to handle the stresses involved, just like the real railroads used (and still do) in order to deal with the rough handling that they would encounter both in the real and model worlds. While the railroads use rope lines to tighten the carfloat sung up to the bridges, the main appliance of “first defence” of dealing with the horizontal (right/left) and vertical (up/down) forces are something which resemble a giant set (or sometimes two sets) of locking pins that are called toggle bars (or pins), as seen below –



      Now, there are PLENTY of nice scale toggle bars (and pockets that they slip through) cast out of white metal or other materials out there on the market, but again, fast and dirty won the day, and I wanted something robust and more importantly, easy to make. Plastruct to the rescue! -


 

      I built them using square tube, with a smaller diameter stock slipped inside that, and a piece of flat styrene strip as a base plate. I made the inner "toggle" long enough to poke out both ends of the "pocket" and then long enough to span the "float" and "bridge" by about 1/4 an inch, or enough to grab. Once glued down in place, I simply sliced it in the middle, ensuring a perfect plumb fit to each end when “docked”. Now, to keep the pin from pulling out of the pocket, I drilled through the entire construct to fit a locking pin (actually, much like the prototype did, too), thus locking it in place, and preventing you from pulling the float away from it’s landing. In the real world, these bars were ratcheted into place, but that's one thing I didn’t have to replicate here! Also, they could adjust the rails right left with another ratcheting device, but that's where the rail joiners (as also seen in the above photo) come in, keeping those tracks in perfect alignment. Until we institute actually moving carfloats, this keeps things locked up tight and derailment free!
      The real carfloats and float bridges suffered years of relentless beating in the course of being used, and that kept things from lining up correctly after a while. I actually have the same problem on my two back float bridges (1 and 1A), and that’s because the carfloats and the float bridges were built separate of each other, keeping the tolerances from being less than perfect. In yet another example of NOT taking pictures of a work project, it took us a few hours of “massaging” the floats and the bridges to allow cars to move slowly from one set of rails to another. My point in all this being, is that the ratcheting of the rails (as seen below) is accomplished by slightly nudging the float bridges to get the rails to line up better.

Aligning the rails on 1 bridge, Jersey City 1974

The construction of the back two pairs of contained apron bridges prevent the use of the rail joiners between them and the Walthers 3-track floats to lock things in place. As can be clearly seen, the left hand tracks are aligned, the right, not so much. But a slight "finger ratcheting" of the bridges takes care of that. Not perfect or elegant, but it works.

    So far, I’ve only been talking about how the carfloats were built and will be operated, but not about the other half, the float bridges themselves. There are particular physical movements to both types being modeled, at least in the real world, and that does bear some mention, as there is a factor of operation to them that can be modeled. If you are following this blog, I’ll assume you are at least moderately familiar with how the electric, or contained apron and the wooden, or pontoon float bridges were constructed and/or how they operated, so I won’t go into exacting detail. I will explain however, that the two types of bridges are/were mechanically different in how they were raised and lowered. To simulate this (and again, add some “play value”), my original “grand plan” was to add a spring suspension to them to simulate the compressive actions (up and down due to the weight of the cars) upon them, and the carfloats as well, in order to replicate the list as cars were pulled on and off. Well, this is all fine and dandy, but there are great problems with that idea when you don’t exactly take your time and build things to exacting detail like I admit I did. ‘Tis far better to have operated smoothly than to never have operated at all, I have become fond of saying! And that's what would have happened if I had tried this, of that I am sure. So with that being said, these "weight differential" actions must be simulated within the "theatre of the mind", but it can be done! Though part of this borders on operations (the subject of Part 3 in this ongoing series!), it does bear some mention here.    
      There are two ways I can simulate proper prototype loading and unloading practices, one being pretty easy for most people to grasp and not bellyache over too much, if at all, and that's using a reacher gondola, as seen below -



      As you can see, the gons has extra-large steps for getting on and off the car (presumably while moving, albeit slowly) and seating for the brakemen to ride the cars back and forth thru the yard, and the body of the car was weighted down with some sort of ballast to provide enough downward force to, in essence, "sink" the float bridge when it was riding high in the water (more an issue with the wooden pontoon floats than other types) to meet the level of the carfloat. Some railroads like the LIRR and Erie had little "doghouses" on a flat car, as opposed to a gondola. Regardless, the railroads used these cars to keep the engine, as much as possible, off the float bridge aprons, though it was not completely forbidden to do so, but rather just smart operating practice. The sudden braking of an engine could very easily snap the mooring lines and cause a float to pull away from the bridge, or worse yet, cause a mechanical failure, causing the steel work to skew and wrench, causing a catastrophic failure as seen below -

And they were even using a reacher car!

      So the point being, you can (as I do) have the crews use a gondola, and until I model one of them faithfully as seen the second of the two gondolas above, an Ertl gondola fits the bill just right, as the gons used in my era were small 34 footers, and not the larger 50 footers used in the later years.......


      And the other way to simulate proper loading/unloading of a float is to double on and double off the cars, and not just pulling everything all at one time, because in the real world, that would be a recipe for causing the float to capsize as all the weight shifted to one side. Instead of trying to explain this procedure, I will instead direct you to the following website that has a very good step-by-step diagram of this "dance" -

     
      So by doing the above "operations", one can simulate the realistic actions, if not the actual stress forces that are present in the operation of the real thing, even to this very day.

      So having witnessed switching carfloats at my pal Dave Ramos’ layout, I have come to realize that not only is switching a carfloat just a small part of the bigger picture, but also that because of that fact, I don’t miss the sight of the bridge OR the float bobbing up and down, listing port to starboard. As good as our standards for our car fleets may be, and our track perfectly aligned, the fact is that our models don’t behave like their 1:1 counterparts, and are far less forgiving in their tolerances. Thus, it’s just as well that things stay FIRMLY connected to the  “water” that they “float” in! In a larger scale like O, this might be something achievable, but in HO, I think that unless you are a watchmaker who is accustomed to working with delicate moving parts, I think this is something best left alone!

      Well, once again I've gone on a bit too long, but I can't help it! Since I also want to talk about the paperwork and how the operators will staff the carfloat staging as well as switch them, there will be a Part 3 in the very near future if I keep this pace up! See you soon!

2 comments:

Riley said...

Great double whammy posts and thanks! I'm with you on the operate smoothly versus never operate mantra. I've only mused about my own system design, and it has ranged from magnetic locks to similar shaft/receiver schemes you are successfully using. It's great to know that you've got something working. I've even considered schemes that would lock both the float in a scale modeled way and then the cart or substructure to substructure in a more robust and very positive way.

As I've mentioned before, I would very much like to have my floats be in play as an operating job (tugboat captain or harbormaster), but I'm going to get at least two destinations in place before tackling that project...

Great posts and info - thanks!

Ralph Heiss said...

Riley - I'm very glad that you came away with some good food for thought, if not just a pleasant read! I agree, it all comes down to 'play value' without making it SEEM like play but rather operation. OF course as I stated, the operation is no fun if it gives you unecessary headaches! My only wish is that I had room to build a pocket terminal elsewhere in the basement (and don't think for a minute that I haven't thought about it!) so I COULD "float" my floats somewhere. Again, I look forward to hearing how your layout and its operations come to fruition in 2013!