This model is another old "Classic" the Railway Breakdown Crane based Meccano Model Plan SML 30 first published in 1930.  Revised in 1934 I would imagine the photographs used were retouched to show the cross hatching on the plates at the time blue and gold parts and sets were introduced no other changes were made. SML 30 could be built with the new  "Outfit L" also introduced in 1934, the largest set Meccano produced. The instructions for this model along with many Super Model Leaflets were included with the set. 1937 was the last year of production for the "L set" and the supermodel leaflets following the introduction of the 10 outfit and all new instruction manuals.   I have had this on my building list for a long time but I somehow have never got round to construct it until now (March - April 2017). I have built my model using mid 1970's zinc/yellow/blue parts perhaps more appropriate for a modern crane, in past times these cranes were generally painted black. I decided from the outset that I would not build the model as the instructions using a Meccano 20 volt long plate motor with a four way gear box but to control each function with separate small motor, with reduction gearing. The original instructions showed a gearbox with four outputs one was the traction drive but I decided the crane was not going to any where so I abandoned this. The model is operated from a switch box with each function controlled by a toggle switch giving forward/reverse/off. I built the frame and bogie more or less as the original instructions but with a few improvements. The frame of the model is a good representation of the prototype shown on the rear page of the instruction manual. Picture shown on the right. This part of the model has some interesting features such as leaf springs, brake shoes on four wheels actuated by a hand wheel on each side. I found the need to make some modifications to this to make it work well, there is a bit of an error in that the construction of the brake shoes makes them touch the track!  There are two screw down stabilisers that pull out from each side again changed from the original instructions.Completed frame shown above The jib was another area of some changes I used curved strips at the top to give a more accurate swan neck as on many breakdown cranes of that period. I also used flexible plates and replaced the standard strip bracing with narrow strips that look better than standard strips. One area I was concerned about was the bearing for slewing or rotation this used part of the ball thrust ball thrust bearing p/n 168 matched with a large 133 tooth gear wheel p/n 27b instead of the sprocket part. I imagined it would not support the crane body and jib without tipping, when balanced was this overcome with a few changes. The original instructions suggested "The use of parts to act as a counter balance weight inside the boiler if you are going to lift heavy loads." However counter balance weights are essential! I used two cast blocks of lead I made some years one on each side of the rear body. I am pleased with the overall appearance of the crane and it works as should all Meccano models! There are many improvements that could have been made but then it would not be SML30. Page created April 25 2017 Revised May 19 2017
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The prototype of the model taken from the instruction SML 30 leaflet. These cranes were steam operated, many had long lives and were in use until the mid-nineteen seventies. In fact British Railways placed an order for twenty steam cranes as late as 1959.   In use they would have been taken as part of a breakdown train to where required then be able to move short distances powered by their own steam traction.