Titan

It gets worse when you have a group of engineers in the pub. We were looking at the differing levels in our respective pint glasses and started discussing how many degrees out of phase our drinking was. We almost got to the point where we were literally drinking and deriving!!

I thought they were integral? Mind you I could never differentiate between them... Even by parts...

What about octagonal signs?

I was getting worried it was a response to my post...

And I won't have to interrupt the journey now if my partner wants to get intimate on the back seat!

If it was a John Deere I suppose it may have had artificial intelligence... oh you mean the dog?

I thought it was the green/red stripped engine that was scared of elephants?

And this is the issue - there usually are site constraints. For example gas mains, water mains and all sorts of other things that criss cross under the railway and can affect the cost and many other things that you have not thought of. And these tend to be more common in populated areas, like near stations for example. Even what appears on the surface to be relatively easy often is not due to other constraints. On one particular straight forward looking station there was a gas main, water main and an ancient brick sewer all in close proximity to the extension. Construction made an error and we were very lucky not to have a sewer collapse, which could have had an interesting effect on the track alignment...

I have been directly involved with the design of a large number of platform extensions in my day job. Signalling is only one consideration of many. Platform extensions that only require signalling alterations tend to be the exception rather than the other way around. I think it is ill advised of you to presume what 'we all understand'.

It seems that you are now in fact agreeing with me in principle that there are in fact other issues besides signalling, but the tone of your post tries to suggest otherwise...

Not so. Underbridges, Overbridges, Embankments, Cuttings, Retaining walls, boundary limitations, and also pointwork and track re-alignment if it is an island platform. There is an awful lot more to consider than just signals and it is rarely just a case of just easily sticking a few yards extra on one or other ends. Add OLE in to the mix and it is even worse!

It's very good! At the risk of being pedantic I think this represents a class 47 power unit in as originally fitted condition. They soon had crankcase explosion relief valves fitted. If you look at the picture I posted on page 1 they are the large round items running along the crank case cover in between the securing screws that you seem to have done so well. As the modification was done very early on the Class 47 would have had them for almost all their working life.

The Deltic Silver Jubilee railtour, 1986. Double headed 37's 37 052 and I can't remember the other one. Departed St Pancras, went to the Midland Railway centre where the 37's were swapped for Tulyar at Ironville. 37's then back on and we went to Malton where we detrained to open topped double decker buses to get to Pickering. Seemed like a good idea to go on the top deck for a good view, until you realised that 50mph and low trees was not quite as amenable as a leisurely sight seeing tour, the charming Rail Riders girls bravely hanging on near the front. Double headed Deltics to Grosmont and back. Then everyone squashed in to the lower decks of the buses having rapidly learnt from experience. Back on to the 37's where the driver tried unsuccessfully to break a coupling pulling out of Malton.Then thrash all the way down the ECML to Kings Cross, the 37's topping 100mph as we raced through the dark. A day I will never forget!!!

Groan x 4!

Wow. And of course if someone wants to model a complete bogie that has been rolled out, the traction motors will help there too.

It should be fairly straightforward. The contact wire is round in cross section, but with a deep groove in it on either side, about two thirds of the way up. Droppers and registration assemblies have clamps and clips that grip in this groove, allowing the underside of the wire to be clear for the pan to run along. The conductor beam is a hollow extrusion, which grips the contact wire in these grooves. Prise the beam apart at the bottom and the contact wire should just fall out.

Police: Do You know why i stopped you? Driver: I was the only one going slow enough for you to catch?

The conductor beam is aluminium and holds a normal contact wire. Both systems use the same type of metals in their construction - a low encumbrance tunnel system will have aluminium registration assemblies holding the wire, So both systems will have components that corrode at the same rate as the other. To be honest were are not really poles apart, we both know that things will corrode. Its just a bit difficult convincing people how much it corrodes in reality compared to how much they think it should... And it can work the other way too, I know of a few items that corrode more than the engineers thought they would. They don't get used any more...

They will, but until they start corroding faster than the equipment wears out, it won't affect the life cost.

I have not suggested it will not corrode at all, just that it will not corrode in the same way that steel rail does. Only a few components in OLE are made out of steel, and those that are are very well galvanised. So as I said before, comparing the way that steel rails corrode with OLE is not valid.

The nuts and bolts holding the suspension arrangement are made from stainless steel. Anything else?

OLE is not made of the same stuff as rails, and has a vastly different rate of corrosion. So please stop comparing copper/aluminium OLE with steel rails as the comparison is not valid.

And it would also help avoid confusion if people stop referring to conductor beam as 'overhead third rail' It is nothing of the sort. It is an aluminium beam into which a standard copper contact wire clips in to the bottom, i.e. the beam is just a rigid support for the contact wire which the pan runs along, which continues either side of the beam as normal supported by the catenary wire and droppers (see pictures on previous page) It is energised at 25KV and any pantograph and train can run along it with no modification required.

Absolutely b####r all. Are people forgetting it rains outside? 25KV OLE works perfectly well in a torrential downpour, a wet tunnel will be a walk in the park compared to that...

All the conducting parts of OLE are non ferrous and generally do not suffer corrosion issues. The supports are either aluminium or heavily galvanised steel, which is very corrosion resistant. I think the corrosion worries are getting somewhat overstated...