Current Activities

The new tyres for fitting to the loco have been in storage at Mt Barker for many months whilst workshop resources have been dedicated to numerous repairs to loco 621 - but there's now a glimmer of light at the end of the tunnel!

Firstly we had to provide 150 timber blocks to support the jacking task. Rx 207 underwent its first stage of jacking at the end of October with the only hassles being related to providing firm enough footings for the jacks.

Unfortunately the retyring work, predicted to take a few months, cannot tie up the concrete loco servicing pad so the jacking has taken place on the earth floor of the shed which has variations in its type and compaction.

207 has been jacked 350 mm out of a total of 800 mm mainly to prove the procedure sooner rather than later on. The loco will now sit at this height for a few weeks until we have reinvented our retyring procedures with the four pony truck wheels.

Luckily, our longer serving employees and volunteers have some experience of what is required. Many years ago at Dry Creek, Ron Williams particularly, was involved with retyring 520's two leading driver tyres so our plan now is to practice the work on the small pony wheels first.

Both photos - Ian Johnston

Updated November 2008

The final step in returning the loco to scheduled services was a test run to Sandergrove on Wednesday 13th August.

This was a success and we now plan to use the loco to run the Southern Encounter and Cockle Train on the first and third Sundays until late November, the October School Holiday Cockle Trains and the Highlander to Strathalbyn on the second Sunday of September and November.

Kevin Marzahn caught the loco (right) simmering away at Mt Barker Depot on Sunday 10th August in preparation for its test run with three very happy loco guys, Craig, David and Ian, perched up front.

More info on rust accumulation in 621's Header prior to Holiday Cockle Train running.

The loco team were looking forward to a busy fortnight of steam Cockle Train running when they lit up the loco on Saturday 27th September in preparation for taking it to Goolwa Depot. However the dark clouds descended when it was obvious there was a serious steam leak from the regulator and no more than 10psi could be raised!

Here are some words from Ian Johnston on what then eventuated.

"We have had some rotten luck with 621 today (Saturday 27th Sept) during its preparation to transfer to GD for the forthcoming CTs. Once boiler pressure began to rise, a significant steam leak from the regulator (via the release cocks) became very obvious to such an extent that from 10 psi, no more pressure would accumulate easily due to the leak. A number of "tests" were undertaken to try and work out what the problem might be but nothing at all showed up.

Ron Williams and I delved into 621's regulator first thing on Sunday morning and found a good reason for the heavy steam leak - No. 3 valve was stuck open at least 1/16 inch. Doesn't sound much but on a 3 inch diam valve, it leaves an awfully big gap. The reason for this appears to be our old enemy - a slow build up of a small amount of galvanic corrosion around the balancing piston, mostly on No.3 valve because it is the last one to sequentially open and hence does not open very often during normal running.

Some more pertinent info revealed itself on Monday morning when the superheater header had cooled down. The bottom chamber of the header is what is called a balancing chamber which is in communication with steam once the regulator has been opened but steam only flows to it (not through it) to apply an equal steam pressure to the underside of the valves to "balance" them so that very little physical effort is required to open them against the boiler pressure

We found a significant amount of corrosion products accumulated in this bottom chamber, so much so that under No. 3 valve, the pile of rust and scale made contact with the base of the regulator valve and prevented it from seating fully.

The amount of corrosion around the balancing piston and its bore was minimal and I was curious how this alone might have impeded the valve closing. The reason for this large amount of rubbish could well be linked to the fact that for 3 months the boiler sat completely idle full of treated water and that the pH in the header could not be monitored and adjusted as could the boiler water itself. So during that 3 months a significant amount of corrosion would have taken place as nature dropped the pH for us. What we will need to do in the future is monitor the corrosion process inside the header on a fairly regular basis until we are satisfied as to what has just happened was more of a one off due to the 3 months of wet storage."

Attached is Ian's photo of about two mugs full of corrosion products found in 621's header although the height of the pile does not show all that well. This stuff, representing about 90% of the total, was removed from the bottom balancing chamber of the header with most of it piled up under the No. 3 regulator valve, this being the prime reason for impeding the closure of that valve and hence the problem last Saturday.

The loco was steamed up again on Tuesday morning and ran light engine to Goolwa where it took over from DE507 to run the final Cockle Train of the day.


And then another problem during the October Running

On stabling the loco at Mt Barker after a very busy and fruitful SE/CT day on the 5th October , the customary listen in the firebox revealed an ominous loud hissing noise, usually associated with a cracked/broken crown stay or a leaky element. It turned out to be the former but instead of the "normal" slow bubbling of steam and water from the stay telltale (leakage) hole, it was running water. This indicated the stay was well and truly broken and because of the amount of water flowing into the firebox, it was impossible to determine if any other suspect stays might have been contributing. Consultation with the boiler inspector confirmed 621 was a no go until the extent of the leak had been investigated and if relatively minor, the leak could be temporaily plugged.

The stay was plugged once the loco had cooled down, but still in a hot but bearable environment with a simple tapered steel plug hammered home hard. This normally works as a temporary stop gap until a window presents itself to remove the broken stay and replace it with a new one. Among all the thousands of stays around 621's firebox, there are 3 rows of 24 flexible crown stays on each side of the firebox (144 total) located along the radius of the inner firebox in the transition from the flat crown sheet to the vertical sides. These stays carry most of the load when the firebox is at its hottest and hence fully expanded. Unfortunately these stays are fairly old - most date back to the 1950s and hence are prone to cracking and sometimes breaking. Once this has happened it is desirable to replace the stay as soon as practicable so as not to overload adjacent stays resulting in the same fate. And if any two adjacent stays play up, it is instant withdrawal of the boiler - and hence the loco. We have previously operated for short periods with one stay plugged and this is acceptable provided frequent monitoring of the situation is maintained - again for obvious reasons.

Ian Johnston's photos shows the results of the leak first up and then the same thing after a bit of a clean up and the plug hammered into the tell tale hole. We will be closely watching that this plug remains in place and no other stays start to leak. The reason the stay head immediately to the left of the crook stay looks different is that it is an earlier replacement stay and rather than rivet the heads over, we now run a fillet seal weld around the head - much quicker, easier and safer than using a rivet gun in a confined space. The 3 blobs across the top of the photo are the "button head" ends of the crown sheet stays - a different type of stay but does the same thing.

The loco was returned to Goolwa to resume duties after a break of just a couple of days.


A not insignificant heavy maintenance task!

As part of our loco documentation Mt Barker Depot Foreman, Ian Johnston, has been compiling a detailed record of the individual tasks carried out on 621 since it was withdrawn from service just on two years ago. These have been presented on these pages as the project progressed.

A small number of tasks were attributable to damage incurred in a minor derailment near Gemmells; a bent draw bar, broken speed recording sender unit and some minor dings to wheel rims and brake rod supports under the tender. All other work performed was due to normal wear and tear along with the age of our equipment requiring some routine heavy maintenance.

The description of the tasks does not indicate the time spent which can vary from a few hours to a number of weeks. Hopefully the list will give "non mechanical" volunteers some appreciation of the scope of the work we undertake with very limited resources and why the maintenance of such "old" machines, which includes everything we operate, is a large task fraught with difficulties due to the age and condition of many bits and pieces.

Click  HERE  to download Ian's report (in PDF format) on the final tasks leading up to the loco test runs and the its return to service on the 17th August.  


Latest - Replacement of Tubes and Flues

As summarised on our Latest News page our hardworking Mechanical Services team had a Christmas present that they did not deserve when routine inspection of the loco in preparation for summer Cockle Train workings revealed water in the smoke box which was traced to an 8mm crack in one of the 20 year old flue tubes.

It was initially thought this could be welded up but removal of the flue confirmed a much more serious and major problem, which resulted in the boiler inspector condemning all flues and boiler tubes. This will unfortunately mean 621 will not be available over summer, and we will have to rely on DE507 and railcars

Apart from an indicative cost of around $50000 for new flues and tubes alone, procurement of material and consequent fitting will be a massive task taking into account our limited resources and based on previous experience other unpredictable maintenance work inside the boiler could well be required.

Here are a few more details at this early stage

• Removal of the flue revealed a stress corrosion problem in the end of the flue tube, hence the crack, hence the leak. Based on the age of the flues, it is believed the metal has crystallised and because of that and the thinness of the flue walls plus a few other factors, BD has had no hesitation in condemning all flues - no good even for reuse as they have been in the boiler for 23 years and are already second hand. Then based on all of the above, the same reasoning has been applied to the tubes. So to cut a long story short, all flues and tubes require replacement; not suprising - they have had an extremely long life.
  
  
• We have 16 flues purchased for 520 in 1994 which can be used in 621. We will need to purchase a minimum of 6 new flues. We have no spare tubes and will need to purchase over 100
  
  
• We hope to have a more accurate view as to where we are heafing within a couple of weeks so watch these pages, and if anyone feels they wish to contribute financially or in any other way to this unexpected setback - please contact us.
  
  
• Obviously work on retyring Rx207 will be put back for the moment - speeding up this work rather than putting resources onto 621 was considered by BOM but was not a realistic option.

Updated to 2nd December 2008

Work on the engine has been essentially halted in order to expedite the return to service of 621.

The key rebuild of the tender, that we were hopeful could be undertaken in the TAFE system, is now likely to be undertaken by volunteer David Groves and his fellow workers at Plympton Steel during voluntary hours. Very sincere thanks to David for negotiating this valuable input.

Updated August 2008

The power cars have experienced minor electrical and transmission fluid loss problems which are being investigated by their "mother" Daryl Simon.

Car 60 has been regularly operating well patronised Cockle Trains with either baggage car no. 82 or a centre-loader. It is also operated a number of charters and trips to Strathalbyn.

In early June it was determined that the car's trailing bogie wheel tyres have reached minimum thickness and steps were taken to exchange bogie wheels.

A spare trailing bogie from Goolwa Depot has been serviced by Phil, his south coast team and Mt Barker fitter Ron Williams. The bogie has been cleaned, crack tested, wheels gauged and axles ultra sonic tested, bolster and trunnion exchanged and bearings and brake rigging refurbished. The car is now back in regular Cockle Train service.

Ivan Marchant's photo of the car was taken near Gemmells on a crew training run on the 1st October 2007.

DE958 has now emerged from a lengthy period in our Mt Barker workshops to rectify problems with its camshaft and related parts, and will haul its first scheduled service on 7th June.

The following account describes the steps that were needed.

Keen observers will be aware that DE958 has not been running for some time. Abnormal noises from two cylinders were investigated and engine valve clearances measured. All settings appeared to be still within clearances. The injection pump timing was then checked and also found to be within specifications.

With information from commercial operator EDI about possible cam lobe wear it was decided to remove the cylinder crankcase covers to allow Craig Dunstan and John Gordon to make an internal inspection. A broken piece of a bolt appeared to be some sort of grub screw and after consulting the workshop manual the component was identified as an oil gallery plug which should have been located in the end of the cross head (rocker shaft) blanking an oil gallery.

Inspections of cylinder L5 proved the plug had dropped out and as a result of a localized loss of oil pressure, damage to the camshaft, cross head shaft and associated bushes had occurred. The entire LH bank of 6 cylinders was consequently stripped of all rocker gear and push rods, large and heavy injection pumps and cross head mountings and cross heads. Several large cooling system pipes were removed along with one of the compressor heads and barrels and the partial dismantle of the compressor air intercooler.

Special camshaft supports were designed by lan Johnston and manufactured by Ron Williams and Ron Norrell to enable the weight of the camshaft to be taken as its three segments were dismantled internally and removed from the engine The worn section of the camshaft was sent to Perth for repairs.

  
Our photos show two sections of the removed camshaft and one of the special plastic lined support jigs

Since receiving the correct new engine parts late last week, a good effort from many saw the LHS of the engine put back together by yesterday despite a rubber seal in a 3 inch coolant pipe expiring. Yesterday a modified 900 class electric oil pump was set up to successfully circulate engine oil around the engine prior to cranking it over without damaging the, by now, quite dry bearings etc. We had then planned to start 958 and if all was OK, warm the engine up, load test in the depot then go for a light engine test run. But things came unstuck one after the other from first thing.

A pool of engine oil (from yesterday's pumping) was found on the engine room floor which was traced to a cracked 1/2" pipe on a barrel union connected to the bottom of the oil strainer in a fairly inaccessible spot. A similar union was not available in Mount Barker so the broken part was cut off and a new 1/2' fitting welded on. All was refitted and tested by circulating oil with the 900 pump - so far so good although about 2 hours lost.

A new/replacement coolant seal could not be obtained quickly from the local agents so it was decided to refit the expired seal yesterday using copious quantities of red silastic - not too many loco blokes will be surprised at that. Pumped all 175 gallons of coolant back into the engine this morning only to find a gasket seal on another joint at the bottom of the plumbing tree decided to leak - the repaired seal was as good as gold. So all coolant will need to be dropped again and the reason for the new leak investigated What makes things difficult is that we are working with parts and materials decades old and corroded making good sealing difficult.

Then it was time to pressurise and check the fuel system and in particular the 6 "banjo" fittings connecting the fuel rail to each of the LHS fuel pumps. In an attempt to save dollars, not always wise as we have again found out, the 12 copper seals in these fittings were reused. Quite often you get away with this but unfortunately not today. Even before fuel pressure was established 2 were leaking and by full pressure all 6 had fuel running everywhere. Enquiries around Mount Barker and subsequently everywhere else established the heavy duty seals are not available off the shelf. We could make new ones from scratch but a quicker approach will be to painstakingly refurbish and reanneal the existing seals and ensure the alignment of the fittings is spot on to each other.

After lots of leak fixing today (24th) and extra battery charging, the loco started easily and from the very first exhaust beat sounded much better than previously . The previous missed beats when the engine started and every now and then while warming up have gone. The engine was warmed up for almost an hour, then run at full revs while not going anywhere with nothing unusual (noises etc) showing up. So it was decided to take the loco (by itself) for a run to Bugle Ranges and return and simulate a load for awhile by heavily dragging the brakes on the uphill bits while flat out in notch 8.

This was done in both directions with no sign of any vibrations - so maybe that was linked to the worn cam lobe causing the L5 fuel pump to not work correctly and/or at the right time. Further proof one way or the other will occur when a decent load is put behind the loco with sustained climbing from Strath back to Mt Barker. The signs are certainly good at the moment but let's not get carried away until the loco has been proven over a greater distance with a heavier load.

While we fixed the water leak from last week, another joint weeped to start with but by day's end had come good. As to whether it is permanently OK will be revealed when the engine cools down. At least we are now quite proficient at draining the cooling system and pumping it all back in again. The refurbishment of the old fuel pump copper seals did not do the trick completely - not unexpected. All 6 were weeping at the end of the test run so new seals will have to be sourced or made then fitted.

Lessons Learnt

Looking at the "big picture" a lot of concentrated effort has been put into 958 dealing with a whole host of problems. The whole task has been a fairly steep learning curve for all considering we have never undertaken major engine work like this on any of our diesel locos. It is interesting to note that the SAR/AN undertook such camshaft replacement tasks with the engine out of the loco - something we could obviously not easily do. There were many times the cramped conditions tested our patience both by getting in each others' way and the difficulty in moving and handling some heavy and large bits - for example the longer camshaft segment weighs in close to 100kg.

Updated 4th June 2008

Not currently used as an operational locomotive

Boiler Condition

• The loco's boiler certificate has now expired. Our boiler inspector reconsidered the condition of the firebox tubeplate and noted that the tubeplate has a record of cracking after each 300km of running.
  
  
• The loco was last certificated in 1995, when over 140 cracks were repaired. At that time it was approved for only five years of further operation.

Problem detected with Wheel Flanges

• Early in 2007 it was noted that the flanges on two of F 251's driving wheels were below condemning level and also that wheel #R5 was a borderline case. The flanges were last routinely measured in early 2000 and at that time it was noted both flanges were very thin. Since then, F 251 travelled 3400 miles up to the end of that year when Rx 207 was recommissioned. This indicates that the distance was sufficient to tip the flange from being very thin to being condemned.
  
  
• From the thickness remaining on the tyres and because the flange is so badly worn, it is doubtful if there is sufficient to allow for a full reprofile of all wheels. Accordingly F 251 is not available for any service until all wheels have been either reprofiled or retyred, which ever may be the case.

520's tender was routinely drained and inspected in December 1998 after the normal running season. This confirmed previous evidence of corrosion and wastage of the underframe, where the tender had been extended down to increase water carrying capacity. Calculations based on the static and dynamic loads on the underframe indicated that the tender frame had reached its design life, having been subjected to over 55 years of ongoing corrosion and to rectify this will require substantial strengthening and long term anti-corrosion coating.

Mechanically, the loco is in good condition, but the boiler and smokebox need attention. In 1994 the loco was converted back to a coal fired boiler by superficially covering over the oil burning apertures in the boiler backplate. This approach is not now acceptable to our boiler inspectors and initial work involving stripping fittings in the cab was commenced prior to discovering the tender corrosion problems, but has not been further progressed. A full rebuild is required to address wasting of material in the smokebox. This will require reproducing a complicated smokebox profile.

The unfortunate outcome of these inspections is that 520 will require over $200,000 of work to put it back in reliable condition. Steam hauled "Southern Encounter" trains will therefore utilise either double headed Rxs or 621 for the foreseeable future