/...Continuation/ In 1938, yet another phenomenon was noticed in the locomotives of our first modern steam class - the connection between the steam cylinders and locomotive frame became loosen and cracks appeared in the zone between the frame and the steam machine. Due to that, in 1939 at the main railway workshop, nine of the locomotives had their steam cylinders dismounted, frames straightened; the apertures reamed and new pass-bolts made for the flange connections of the frame.
In the same 1939 , locomotive 01.0.5 broke her right frame joist on the front angle of the axle - box cut-out of the first driving axle.
In the beginning of November 1939 , was announced an auction for the delivery of right frame joint according to drawing ¹ 8.04 , however competitors did not appear. To the questions adressed to BORSIG, HENSCHEL and KRUPP, answered only the last company; suggesting to deliver two joints (left and right, in respect to drawings ¹¹ 8.03 and 8.04 ), for the milling of a single axle was technicaly impossible.
The conversations began on December the 27 th and successfully finished on December the 30 th 1940 , when an agreement was concluded for the delivery of two frame plates, all together coming to 419 100 BGN, as the term of delivery was 8 months. Actually the frame plates arrived in Bulgaria on 16 October 1941; received by a committee in the main railway works on 18 November, as later on was started the repair of 01.05 locomotive. The Fr.KRUPP-Essen company initiated itself several researches in the drawings documentation of our steam locomotives and by its representative in Sofia - Dochev, Kosta P, on 17 November 1941 under a signature Lowa-A-¹ 378 , it made an official proposition for the remaking of our 01 class into one of the follwing three variants of the “Drilling” system: 1D1-h3, 2D1-hÇ or 1 D2 -hÇ .
After the establishment of business relationships and the preliminary negotiations, the KRUPP Company sent an offer on 18 February 1942 , which was concerning the reconstruction of 5 locomotives of the 01 series type B 1-4-1 17 a nd a “ Zwilling” machine, into type B 1-4-2 17 and a "Drilling” machine.
In order to avoid the high transportation costs, the company suggested to conduct the reconstruction in the main railway workshop in Sofia , under the guidance of their specialist, instead of into the KRUPP's factories. Drawing ¹ 17232 that was supposed to be used during the reconstruction, was also attatched to the offer. The parts marked with red color were those who had to be dellivered by KRUPP and those marked with blue were to be modernised in the main railway workshop – Sofia .
In the offer were enumerated the parts that were to be delivered and the most important of them were:
- Three new steam cylinders, along with the slide valves and a kit.
- The second and third driving axles and a kit.
- The internal crank moving assembly and a kit.
- A double-axle bogie with sliding bearings in jacks of Frideman, a kit etc.
In the preliminary conversations the head administration of BDZ wanted to replace the front driving axle of O 850 òò with a O 1000 òò one, but the company responded that this would weaken the front part of the locomotive frame, and after that the head administration renounced its suggestion.
Examining the offer was assigned to three of our best locomotive specialists in these times: engineer Gotsev, Stoyan – chief of the main railway workshop – Sofia, engineer Petrov, Petar – head of traction mantainment department in the main administration and engineer Milev, Nikola – head of Sofia and traction depot. This comission composed a written statement, dated 27 April 1942 , which aprooved the suggested offer. The head administration of BDZ was ready to conclude the contract. The sum of 17 millions BGN demanded for the modernisation of the first five locomotives was supplied. However, on 23 June 1942 , a letter arrived from the KRUPP Company, saying that the company was unable to deliver the necessary parts (probbably due to the enormous amounts of orders for the war) and therefore asking for a postposal of of the order in time. This is how finished, and subsequently due to explicable reasons ( the exit of the war and the post military situation ) never conducted the modernisation of class 01.00 locomotives.
Later on, following another discussion in Bulgaria, a new, simpler decison was taken – each time a locomotive arrives in the main workshop for an overhaul, to drive in cast-iron cyllinder mantles or to mould new cyllinder blocks, so that after the final processing, the initial drawing diameter of 640 mmto be shorten to 595 mm. thus lowering the cyllindrical forces tension in the consolidation zone between the steam machine and the frame of the locomotive.
As we have already mentioned in another place, the locomotives of 01 class were in a terribly poor condition at the end of the Second World War and most of them gradually fell into disuse while waiting for overhaul. This is why the decision of diminuition of the cyllinder diameters was being realised in 6-8 years. This was also helped by the fact that after the first few overhauls, the replacement of the cyllinder blocks was prefered than driving in of cast-iron cyllinder mantles. Subsequently, when by one or another reason the new cyllinder blocks had to be moulded, they were manufactured in their initial size of 595 mm. And to conclude the matter of the cracks in the frame and the consolidation of the steam cyllinders, we could say that after the diminuition of the cyllinder diameter and while the trains being served by those locomotives were comparatively light, the break-downs of the descripted character quieted down.
However, very soon all of the fast and normal trains on the main lines reached gross weights that were equal to or above the utmost potentialities of the steam locomotives. As a result, later on 1956-1957, in a number of cases the cyllinder blocks were weakened from the locomotive frame, mainly the left ones. The reason for this phenomenon was the strong greasening of the contact surface and the bolt connection between the block and the frame by the Knorr pump, which was factory installed on the left side of the steam chamber. Initially, grease-collecting tins were installed under the Knorr pump, in order to collect the pump wasting oil and condense, leading them away of the node.
At the same time, in the Railway Factory “G. Dimitrov” was developed a constructive documentation for the shifting of the Knorr pumps. They were mounted on a special bracket, on the right side of the locomotive, under the side platform between the third and fourth driving axle. The bracket which was fixed on the locomotive frame is a welded construction of steal plates (similar to the one of 11.00 class). The shifting of the Knorr pumps itself was carried out from 1959 to 1962, while the locomotives were entering for current repairs or overhauls.
With the increase of the gross weight of the trains, another old familiar phenomenon reminded for itself – the cracks in the frame plates (beams) in the zone of the axle-box cutting. Experts said that in terms of the whole contingent of locomotives of this class, later on 1956 and during their intensive use, this phenomenon was observed on the average 1-2 times per year. Of course it was no longer thought about delivering new frame beams. In the Sofia Depot was acquired a technology for their welding, as speaking in short, this is what the sequence of welding was: dismounting of the first driving axle and return of the joints under the driving-axle on their place, positioning the locomotive on a leveled track with an extra support of the frame, release of the frame connections immediately near to the place of the crack, exterior V-riveting with a pneumatic gun on an approximately 90° angle in a 700% depth of the beams’ thickness (90 mm). Riveting from the interior part, welding with high quality electrods, while deep cleaning the slag and pauses after every welding layer until the complete recovery the the beams’ section of the interior and exterior sides, abrasive shaping of the surfaces after the completion of the welding, annealing the place of the welding with wooden coal in a special container, embracing all of the parts of the welded place, and finally painting, mounting of the first driving axle and all of the other dismounted or weakened parts. In terms of time, all of the operation in depot conditions was taking 2 or 3 days, as only the welding required about 10 and 15 hours.
The biggest part of the exploitation life of the locomotives class 01.00, passed in the Sofia Depot. Until 1965 this is their only home and during all that time they were the main fast series of the Sofia Depot. They served trains on the traction branches: Sofia – Plovdiv , Sofia – Pleven (several years to G. Oryahovitsa), Sofia – Karlovo (several years a pair of season fast trains to Burgas), Sofia – Dimitrovgrad JZ (in the past – Tsaribrod), and at the end of the period Sofia – St. Dimitrov (today Dupnitsa) as well as separate trains Sofia – Vidin . /To be continued.../
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