Titan

It is all down to the loading. The Hexagonal ones shown in post 1827 are anchor structures, and are both deeper in width as well as height and also have struts to help take the load. On others the section is decided according to the width of the portal and the number of registrations that they will take. There is a reasonable amount of standardisation, For example one of the portal boom sections is identical to that of the two track cantilever, so that the same fittings to attach the registrations can be used for either.

I don't think the class 89 were axle hung, more like bogie mounted as per HST and most other BR electrics (notable exception being class 86 which were axle hung)

I wonder if it is providing cover for a 92 that would normally be at Dollands Moor?

Yes there is. It warns against using a DCC version with an old DC controller. The output of which can be so noisy that the decoder does not recognise that it is on DC and therefore does not respond. The peak voltage they put out can also be very high, which may cause damage. Try putting a small non-electrolytic capacitor in parallel with the controller output, and see if that helps - but don't turn the power up too high!

A while back I was in hospital with a complicated fracture. In the morning the nurse asked me 'How do you feel?' I responded, 'I run my fingers gently over the object in question, would you like a demonstration?'

They actually borrowed one specifically for its high track forces. IIRC The standard was that nothing running at any speed should impose a higher track force than A Deltic running at 100mph. I believe that Class 47s were designed for 100mph but restricted to 95 for this reason. As a side note it was discovered that there was not a sufficient scientific evaluation of this until just after the Deltics were withdrawn. So 55015 was dragged off the scrap line and taken to the RTC Derby and put on a special test rig to measure it!

Yes, if you try to run a train at high speed without the profiles developed by BR with the APT project this is what happens to your track after just one run... The aftermath of the 206 mph world speed record in France in 1955. Without the APT the TGV etc. would not have been possible. Indeed the prototype TGV was also gas turbine powered and articulated, pretty much a non-tilting APT-E painted orange and with one extra car:

When I was a trainee technician we got sent to various depots to gain traction experience. One of my colleagues got sent to Crewe, where he somehow managed to get involved with the Crewe open day. He was a bit of an extreme rail nut, those of us who thought that we were rail enthusiasts had nothing on him. He made suggestions as to which locos would be good to display. His suggestions may have appeared to be somewhat odd, until afterwards when it was found out that he just invited locos he had not copped yet so he could get their numbers more easily!

TTS version?

No provision for a second man. Was it a strike or just a boycott of the APT-E?

When I started my Training at the RTC I noted this unusual four wheel wagon in the yard with a lot of short lengths of rail stacked up and bolted down to it - presumably for ballast purposes. I had no idea what it was or it's significance other than it looked quite interesting!

Not quite, the aim on full size is usually to get the offset as near zero as possible at the center of the span. This ensures that when the wind blows then the wire has to move further at the center of the span before it risks falling off the edge of the pantograph. This means that the contact wire should be at track center or close to it at mid span irrespective of whether the track is straight or curved. However in this case it is one aspect that I would not recommend following for the model. You are not going to have to cater for wind, and in order to achieve a zero mid span offset the spans on a model railway curve would have to be even shorter than they would otherwise be. In any case the shorter the spans in real life, the less the wind can blow the wire off, and the greater the permissible offset at the middle. By the time you get to model railway span lengths the permissible offset would be pretty much equal to the full 15 inches anyway.

Got my non-sound version yesterday. Ran for the first time tonight and it is absolutely superb. The detail and fidelity have to be seen to be believed, and it ran quite smoothly out of the box. No doubt it will improve with time. Some minor issues - the back to back of leading wheelset of PC1 was too wide. However the very clear exploded diagram showed me the detail I needed to put a screwdriver in just the right place to lever off the the retainer of the bogie safely without leaving a scratch, and then removal of the wheelset was easy. A squeeze up on a back to back gauge had it sorted and it was replaced and she ran beautifully. Electrical connection between the two trailer cars was a little stiff. This made it somewhat awkward to couple. I was at first worried that some of the pins might not be aligned. I checked and checked again and all pins seemed straight and true. Followed the instructions on coupling to the letter and did manage to get them mechanically coupled but the electrical connector was not fully home. Lifted the car back up to 10 degrees again and the electrical connection clicked in. I expect this will get better in time as I believe the connections will loosen up slightly. Slight scratching on two of the joint modules. This looks like it was due to them all being packaged together and they must have rubbed on each other during transit. The rest of the packaging was superb. The book, the manual and the exploded diagrams are excellent. This is an outstanding model, it just oozes quality and finesse. Feels like I have bought a Rolls Royce for the price of a Jaguar!!!

I think the problem is that people are not used to crossing in front of something travelling at high speed. Most people cross the road where the speed limit is 30mph, and you only need the car to be a relatively short distance away to be able to cross safely. The bigger the object and the further away it is the more difficult it is to judge the speed - an extreme example is how slowly jumbo jets seem to be moving when they are high in the sky. So when someone sees a train quarter a mile away, which does not seem to be moving that quickly, they judge that they have more than enough time to cross without realising that they may have under 8 seconds before the train is upon them.

I thought a non-electric hoverboard was a skateboard? This looks more like a non-electric segway. Or even more like the back axle of a child's tricycle...

When I was driving them you could make 5mph from a standing start with a tractor half the size of the one in the incident, and with a fully loaded trailer twice the size. With the low gearing and huge amounts of grip pulling away quickly was not a problem. And with the semi automatic gearboxes top speed could be reached very quickly - top speed being limited by top gear ratio and governed engine speed rather than power.

Yes they were, and I can testify that the pantograph works very well. Although they are very nice in themselves, they were unfortunately the wrong type for a class 87, presumably taken from the parts bin of continental electric locos.

Bear in mind that all tractors are capable of at least 20mph, Modern ones similar to the one in the accident with the relatively small trailer are powerful and capable of up to 40mph. It could have got across the railway as fast as any lorry, if not faster.

I thought that the usual procedure was to instruct the crossing user to call back when the crossing is clear, and until then no train would be permitted. If the user fails to call back after a reasonable time, then the next train would be sent through under caution so that the driver can either stop short of the crossing or confirm that the crossing is clear.

One question, Does this loco manage the same maximum T.E. on diesel as it does on electric?

Don't you mean MLF? MILF means something quite different... unless that was deliberate for comedy effect!!!

Hmm. Maybe that explains my rather large electricity bill...

I think it's a large brick building with a clock on the side of a house Well I suppose a clock is a time machine of sorts!

Actually it won't, Hurn Road is to be closed and the new alignment will pass under the bridge that it currently uses. Bit of a turnaround a road being closed so it can be used as a railway!

It is to do with what is called 'along track drag'. When the wire moves due to temperature change, the cantilevers and registration arms move through an angle to accommodate it. The closer you get to the balance weights, the bigger the angle required to deal with the extremes of temperature. If the equipment is set up correctly, the angle should be about zero at the average UK temperature, but at on very cold or very hot days there can be quite a large angle, especially on headspans where all the movement is handled by the short registration arm only, as opposed to the whole frame up to the mast on a cantilever. The real problem this can cause is tension loss or gain in the wire. With a registration at a large angle it is not pulling the wire perpendicularly. If you resolve the forces - simple triangle geometry - then some of this force is being added or taken away from the wire tension - the arm is basically pulling on the contact wire one way or the other. More than 14 registrations from the mid point and the sum of all these forces, known as along track drag, can add/remove a significant % of the tension by the time you get to the mid point anchor on a cold/hot day. There are different limits according to type of construction - If it is cantilever only you can have more structures than headspans, as the cantilevers would move through a smaller angle for the same movement in the contact wire and not affect the tension as much. These days since headspans are rarely used, the number of masts is not so much of an issue and the overall distance from midpoint is more dependent on how much movement the tensioning devices can accommodate.