BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

When you say "a single steel casting", weren't the tubes usually split longitudinally and bolted together?

 

Both...IIRC think the driving axles are in 'split' cannon boxes...

 

Initially, solid type axleboxes were used. This was changed to split type axle boxes for later locos. Split type axleboxes are wider that solid type axleboxes across the manganese steel liner plates. This means that locos designed to use solid boxes cannot use split boxes without major modifications to the frames.
Sorry slight error above. Solid and and split bogie axle boxes are the same width across the liners. Split boxes for the leading, driving and trailing wheelsets are 1/2" wider across the liners than solid type axleboxes.

 

The degree of variation between outwardly similar locos never ceases to amaze, but for the none driven axles one would expect these to be the same as on 71000 ?

The hornguides are welded in, so for the driven axles the brief might be 'what be the biggest axle/ bearing combination we can fit in 'ere please' ?

 

I see Tornado has split cannon tubes on the bogie axles - see attached image from their site. Presumably the bearing manufacturer just produces the bearing, no doubt off the shelf to a metric dimension, on the basis they probably don't want to make one-offs, with the user coming up with the axlebox and cannon housing. All the references in "SKF Axleboxes for Railway Rolling Stock" of 1958, which covers steam / diesel / electric and coaches/wagons, and cannon boxes, refer to spherical roller bearings rather than tapered. Couple of pages attached. These bearing references appear to still be current looking at the SKF site.

 

As with many things Hengist, there needs to be some liason and discussion with carers of 71000, 70000 & 70013 about their little problems.
Water ingress into Cannon boxes is clearly an issue even if its one that takes decades to create problems

 

Regarding water in the boxes, they need to talk to the A1 Trust, who changed from oil to grease to prevent this, following corrosion problems. The key thing appears to be to totally fill the cannon box to prevent ingress of moisture, and keep it full by regular injection of more grease, using the vent as a tell-tale. However I'm not sure whether the bearing have been check since - I will try and find out.

 

Just a little example of the cannon boxes on the 401 Barclay at SRM, we stripped these down to expose the spherical bearings and cleaned all the existing grease out, with the muck and steel fragments from previous wear, and then completely repacked them in a special grease as advised by SKF, IIRC, note the vertically split boxes which have mang/steel liners welded to the sides in mang/steel liners welded in the guides. There was no apparent adjustment so we had about 2-3mm clearance max between liners. Yea, plenty grease applied on assembly and boxes topped up by grease gun afterwards, until it came out the vents.

 

I was a bit confused by this posting until I realised it was not a Barclay but a Bagnall and that they aren't cannon boxes. A cannon axlebox is where the two bearings are housed in a common rigid housing which is effectively a tube. This helps maintain the precise alignment between the two bearings. Have a look at: https://tanfield-railway.blogspot.com/2018/11/darlington-locomotive-works.html part way down for a good illustration of a cannon box.

 

I'm glad you said that, Steve. I was on my way to Specsavers!

 

Yea, well I am on my way to the dole after those clangers! So glad you good folk out there can keep us right. Actually I was that keen to do the reply that I did not concentrate on what I was putting down, note to self, check everything you do 2x, or if on this forum, 10 x +1.

 

Bin there, done that, got the brickbats!

Always remember: you are not alone!

 

Theres always a place for a slim fella whose handy with a Grease Gun John...

 

To help to keep water out of the roller bearings, the locomotive owners MUST issue instructions that under no circumstance are pressure washers to be used on the wheels & frames when cleaning the locomotives. It is an instruction which the NSWGR issued in the 1940's after the 38 Class entered traffic. When 3801, 3820 and 3830 were in enthusiast/heritage service, said instruction was mostly followed.

British locomotives, with spoked wheels would be more susceptible to water ingress than our 38s with Boxpox wheels.

 

The drawings we have are for "Application of Solid Type Cannon Box for Leading Bogie (Timken RF8835)". So that's what we're developing our CAD models for. Interestingly, the outer seal on the Timken drawing is leather. We should be able to find a more effective modern substitute but we will be talking to Timken about that. The original drawings show "oil filler plug", "oil drain plug" and "oil level indicator". However, we've seen a photo from 71000's bogie cannon box which clearly shows an adaptor and a grease nipple, thus confirming that oil was changed to grease at some time in the past. Sheff, thanks for your comments. We were wondering how the grease was retained around the bearings. Inboard of the bearing, there only seems to a flinger so filling them full of grease sounds like an answer.

For the driving wheels, it will bit of a challenge to determine the exact drawing to use as there were both solid and split cannon boxes specified for class 6

SL/DE/26071 APPLICATION OF SOLID TYPE CANNON BOX FOR LEADING & TRAILING
COUPLED AXLES

SL/DE/26072 APPLICATION OF SPLIT TYPE CANNON BOX FOR LEADING &
TRAILING COUPLED AXLES

SL/DE/26073 APPLICATION OF SPLIT TYPE CANNON BOX FOR LEADING &
TRAILING COUPLED AXLES

 

Note standard tanks comments about the width between the liners being different; as the horn space is now set - its a question of what fits and then getting the bearing manufacturer to advise what they have that suits and what journal that will take... Bear-ing mind also that the centre axle/ bearings dims might be different again and possibly unique to Clans...

 

Sheff I note that you said "and keep it full by regular injection of more grease, using the vent as a tell-tale". On the Class 6 bogie cannon box drawings, a revision in 1960 removed the vents. Anyone have any idea why?

 

Stop water ingress maybe ? 1960 - do you think that drawing was ever used? What happened on the Brits?

 

Good points! Water ingress has to be the favourite for an answer especially given the warning about presure washers listed above. Was the drawing used? This web site http://www.fraserker.com/britannia/ has a number of pictures of Britannias cannon boxes but I can't see a vent pipe in any of them. Does that mean they were removed or are they just hiding from the photographer? Looks like a visit to a loco is needed!

 

What a treasure trove of photos, think i spotted a couple of vent tubes intact on the driving axles, seem to have been pinched off on the bogies ... so that was the prototype set up - how does this compare ? with DoG 71000 -(has she still got her boiler off so we can see ?)