WHAT CAUSES MINI BUCKELS?
WHAT CAUSES MINI BUCKLES ON RAIL LINES
I Spent several years in South Carolina , invited by Harsco Track to demonstrate the ability of the dStresen system with the intention to buy the rights to manufacture my system .
We were in Georgia on a rail line waiting for a goods train to pass through and we had use of the passing lane which was a old rail line with lots of gaps so in theory there was no way this line could form lots of compression or tension .
There were trees in clumps and gaps , so you had shade and sunny gaps on the rail line ,
so I decided to set up the gear in a sunny spot while we waited for the goods train to come by .
We started recording the rail temps and the SFT and soon discovered that the gappy line was warming up and my dStresen system was saying that we had a rail line in compression and the forces were building higher & higher , the goods train arrived and we packed up our gear and moved on .
WHY DID THIS RAIL LINE WITH LOTS OF GAPS FORM COMPRESSION ?
Before I say why there is another story covering what happened on the Georgia rail line that occurred in N.Z. and the very same phenomenon occurred before I was invited to the USA .
A length of rail line just north of Auckland , some 150 meters in length needed to be adjusted to 30C SFT .
I set my gear up in the sunny spot with out thinking to much about the location etc . I was some 20 meters south of the cut & weld position with the dStresen recording the SFT numbers , I noted the line to be in compression and as the rail line temps increased so did the compressive load . Now at this time the rail had been cut and the welding crew had worked out how much rail to cut out . The weld crew were working in a shaded area and south of me was a level crossing completely asphalted over so there was no way the rail line could escape this lock up .
The small length of a rail cut out was picked up by me and placed into my van , the line temp in the shade area next to my sunny spot was very slowly warming while the area I was measuring just kept warming up . Now the Sun was coming up and over the tallish trees and now shinning on the whole rail line being adjusted , the compressive load remained until the rail temp in the shaded area became the same temp as the sunny area and the compressive load simply evaporated .
The other rail line was duly measured and a small length was sawn off and I placed this length in with the other bit of rail and there was a obvious difference in the lengths of the 2 bits of rail .
I had a meeting with the rail engineers who by now claimed my system to be wrong so I asked them did the 2 rail lines up & down have the same SFT , the answer was yes , so I produced the 2 bits of rail and placed onto the table and it was obvious that one bit of rail was longer than the other some 32 mm longer . Now the longer bit was the correct length and so the short bit still had the SFT quiet a lot lower than the correct length , so the adjustments were not that flash one might say .
When the 2 engineers saw the 2 lengths there was total silence , what could they honestly say so I picked up the 2 bits and headed back home .
I was contacted to say that I was no longer welcomed on any Kiwi Rail line .
SO WHAT DID I LEARN FROM THIS EXPERIENCE
This is the reason for MINI buckles observed on rail lines in the beginning of the summer temps . Shade on the rail line acts like a block between the sunny parts and the next shaded area so there is no escape for the rail in a sunny area and the compressive forces can grow into a large force creating a mini buckle that is just for the day as I have been asked to measure where mini buckles are observed the next day or some days later and the numbers look just fine , up in the 30C SFT range .
Back to Georgia , USA the engineers could not understand this phenomenon but if we had a strain gauge like we used over at the TTCI in Colorado , the strain gauge would get the same information as the dStresen system .
What is the number one reason for a mini buckle , non locking ballast 2nd the trees shading the rail line . I have noted that granite ballast does not work as well as the basalt
DEVELOPMENT OF THE dStresen SYSTEM .
In the mid 1990's I was given a brief by Peter Ellery about inventing a method to measure the stress or zero position of a rail line , at this time the term Stress-Free-temp was not used here in N.Z. .
Peter was interested in what I was up to in my spare time and my story was about using vibration to stress relieve engine blocks .
I said something that got Peter's attention , when one picks up a guitar and strums the strings you create a vibration that is converted to a sound perhaps this could be the answer to a rail line .
For some 6 months I played around with different ideas until I recalled a method that I used to record a before and after on large steel structures that needed the welds to be stressed relieved , this method gave me a clue as to how to get the info out of a rail line .
So I was effectively using a tune bar but did not understand this and the idea in the work shop worked real nice .
So I set up a tune bar and from this point I was able to gather lots of info from NZ Rail lines . It took some 5 years of collecting information before I was able to have the logarithms working .
At this time a gentleman by the name of Graham Gilkerson of ITL New Plymouth was keeping a good eye on what I was doing , and helped me to use the NI software to build our program on and Allen Hooker a expert on electrical designs helped me to set up a system that we are using to this day .
The most important invention for me was the dual tune bar and measuring a rail line takes just 35 to 40 seconds once the gear is clipped to the rail head .
I have worked on many rail lines across Australia and have had the rail line cut on my predictions some 150 plus times and have not been found wrong .
INVERTER ISSUES .
Looking back to the early days of development we used very light weight inverters thinking that small and light weight was the way to go but unknown to us we fell into a trap with out realizing that we needed a pure sine wave electrical supply like you get from your main supply to your house or work place .
The cheapo's use a square wave and this will systematically undo the software bit by bit which makes one reboot the computer and try again until nothing happens at all .
I was put onto a very knowledgeable human being and was soon correctly put on to a pathway of success , I was buying junk systems , with in the day I soon owned a pure sine wave inverter and have never had a computer melt down again .
READING THE BALLAST .
The dStresen system is able to give accurate info on a ballast that is not working effectively and this is something that some engineers have difficulty recognizing ,
there is the belief that the SFT does not change simply because there is no effective way to measure unless a strain gauge is used .
I notice this very quickly as we have the sun warming the rail line and the stress numbers are changing very slowly but the temp no's are changing very quickly so there is movement between the sleepers and the ballast that is not able to hold the loads or force of the rail line .
On a 60kg rail 1 degree C of temp change is approx 1 ton warming or cooling , the classic rail for this is the line between Sydney and Melbourne where there is a lot of granite ballast used that is just not working , in-fact is just not worth measuring until the ballast is sorted out and made to work .
NOTES ON THE NEW BOGGABRI LINE .
I was hired to check out the new Boggabri rail line to measure the SFT . This rail line
is used for shipping out coal and the rail line temp's were on the cool side , around the 20 to 25C . Not a good temp if the line does not get any more sun for the day .
We were getting SFT numbers up in the 55C SFT and I felt that we were not getting the full story and I was thinking that the SFT numbers were much higher . On the strait sections of the rail line we noted that the rail was very strait , in other words was under a massive tensile load , we cheeked the measurements from the monuments and this was telling us that the rail line on this curve had pulled it self into the curve by many center meter's .
A verse crew was sent in to take a reading and we recorded 47C at a certain location and the verse crew would have gone in there with even cooler temps than we had so I bet their numbers would be even lower than ours , the verse crew recorded 42C , PERFECT or so it seems .
DEVELOPMENT OF THE WIFI SYSTEM .
2 years later we are hired again to remeasure the line , takes several days at every 500 meters location , some 40 km's and we could not use our H/Rail on the rail line so we were able to use the wireless set up and Bryan Finnerty my N.Z. guy who travels with me all over the place walks the dStresen system along with it's own power supply carried on his back is able to get to the most difficult parts of the rail line and set up the equipment and I am able to collect the info from hundreds of meters away in the pickup .
The wifi set up was another break through but depends on battery's that do not last forever , so we have 2 power packs , one on the charger and using one on the job and swap over every now and again .
A warmer time of the year was chosen .
Now the line temps were around 40 to 45C and strait away the SFT had moved into the correct position , in other words when the ballast was laid at these temp's which were hot days .
The location that the verse crew had measured turned out to be 59C not 42C .
After some detective work we discovered that the ballast had been dropped in very hot conditions . This is a common mistake on new lines if the engineers ignore the fact that the rail line will move around freely even if the rail has been clipped up at the correct 40C before the ballast drop .
So a real hot day and the ballast traps the rail line at these higher SFT numbers as the dStresen system showed .
WHAT HAPPENS TO RAIL UNDER VERY HIGH TENSILE FORCE .
Now if the rail line is under a large force in TENSION and we saw SFT numbers above 65C the rail line will rarely go into COMPRESSION but when the rail temps start falling below 40C you now have some 25 tons of force coming into play , could possibly be 30 tons before the rail line starts to move and pull the rail line in to the curves .
We checked the area where the coal loading wagons is carried out and the rail line is in a big curve and a quick inspection you can see that the ends of the sleepers have good sized gaps which proves the rail on a cool night pushes the ballast into the inside of the track .
The rail line appears to have a memory and will return to its hot position during the day as temps rise back up to 40C plus . Like operating a whole lot of mini hydraulic rams but one does not have any control over the force .
A rail line that has very high SFT numbers is not likely to cause too many problems compared to a rail line that has very low SFT numbers then one can expect some real challengers .