How are bogies attached to bodyshells/locomotives etc?

[Cowley]

I feel like I should know this really but what needs to be released apart from ancillaries like brake equipment, traction motor cables etc to lift a coach or multiple unit body off its bogies? Are there release pins/bolts etc, and how are they actually accessed?
Also would the process differ compared to something extremely heavy like a 120 ton diesel locomotive?

Any thoughts on this would be very much appreciated.

 

[37057]

A thread not too long ago here:

https://railforums.co.uk/threads/bogie-chassis-connections.214776/

 

[Islineclear3_1]

Not an answer to your question but I think some depots "drop" bogies into a pit, rather than lift the body.

 

[Cowley]

A thread not too long ago here:

https://railforums.co.uk/threads/bogie-chassis-connections.214776/

I hadn’t even noticed that one! Your reply in that thread was very useful @37057 thanks for that.

Not an answer to your question but I think some depots "drop" bogies into a pit, rather than lift the body.

Well you make a good point actually, although it’s the attachment side of things that I’m most curious about.

 

[Richard Scott]

As far as I'm aware most are held on by sheer weight but have straps linking bogie and body in case loco overturns. Class 44/45/46 had a body mounted bracket affair, which held bogies in place if loco overturned. There is a lug on bogies where it locates but not physically connected. The brackets need removing before body and bogies can be separated; hope this rambling makes sense?!!

 

[co-tr-paul]

A couple of shots from the GWR Night Riviera fleet.

Tap on image to get correct view @

 

[Cowley]

As far as I'm aware most are held on by sheer weight but have straps linking bogie and body in case loco overturns. Class 44/45/46 had a body mounted bracket affair, which held bogies in place if loco overturned. There is a lug on bogies where it locates but not physically connected. The brackets need removing before body and bogies can be separated; hope this rambling makes sense?!!

Thanks Richard. Most useful.

A couple of shots from the GWR Night Riviera fleet.

Tap on image to get correct view @

Great photos Paul. Quite a bit to study there.

 

[pcrail]

... but have straps linking bogie and body in case loco overturns.

This a very common miss believe. The straps are basically there, that you can lift the vehicles with the bogies attached. Ok, in light derailments the straps may help a little bit to keep the bogie at the carbody, but they are not designed for this.

It is correct, that most vehicle just sit by their weight on the springs of the bogies. Some bogie designs include a cross member over the springs. In this case, the cross member is bolted to the carbody with a few bolts, sometimes only four.

 

[edwin_m]

Bogie detachment was considered to contribute to the severity of the Potters Bar accident: Microsoft Word - Potters Final.doc (railwaysarchive.co.uk)

Standards that prescribe strength requirements for body-to-bogie connections in vehicles should require that the potential modes of failure are determined at the design stage, and that action be taken to ensure that the integrity of the vehicle body structure is not compromised if the connection is overloaded.

However, according to what someone senior at the former BR Research said at the time, their modelling of the Great Heck derailment suggested it wouldn't have happened, had the bogies been attached less securely.