Suzie

 

I was wondering if anyone has ever removed the body of the underground ernie Bachmann series (not the inspection vehicle but all the other units from the serie)? 

In other words what kind of chassis/motor/drives is there?

The chassis is a central motor type with the capability to drive all axles, but the implementation used in the Underground Ernie models only drives both axles on one bogie (two car EMUs don't really need any more traction). I suspect that you could buy a new double-ended motor and with the parts from two chassis make a four axle drive chassis, and do away with the traction tyres if you are keen. The chassis is DCC ready with an 8-pin socket. As supplied top speed is not very high (I would guess about a protypical 30-40 mph in 7mm) so you might like to consider that if remotoring. Current pickup tends to be a bit temperamental out of the box, but they get better after ten or so hours of running - another reason to remotor and do away with the traction  tyres.

 

...The cost of building a new tunnel as recently as 1952 for barely 20 years use would have been seen as legitimate investment in those early BR days with then-new electrification and a "brave new World".  We cannot predict what technological change might occur over 20 years nor what changes there might be to traffic patterns.  

In the early '50s BR the nationalised railway was still very split into it's constituent companies and the investment programme was still that of the LNER from twenty years earlier when the modernisation was started. The Hope Valley route was LMS and therefore I am sure not a consideration with the traffic being predominantly from LNER locations and to LNER locations, therefore logical to go via the LNER route and it would have been thought silly to go via the LMS. Had there not been nationalisation I am sure things would have turned out very differently... EM2s on Sheffield - Manchester - Liverpool passenger services via the CLC route anyone? A major container port on Humberside with double headed EM1s to Trafford Park?

... Incidentally Manchester to Altrincham was converted yet again and is now 750Vdc as part of the Metrolink network.  Is three voltages on one line some kind of record?

Damage to silicon devices can be cumulative. When a silicon junction is subjected to a higher voltage than it can withstand the insulation breaks down and suffers a small amount of damage. Eventually when subjected to enough abuse the insulation becomes sufficiently compromised that the device fails - usually as a short circuit.

Just because a decoder survives once does not mean that it has been properly protected. Even Zener diodes can be a little slow to react to a sudden application of high voltage and fail.

It looks like it should be OK in practice since it is current limited to 2mA and most decoders will draw more than that even while idle (typically 10mA or more) due to the regulator maintenance current. You could put a 4K7 resistor between the red and black wires of your decoders to make sure that they will not go above their safe voltage while 2mA is applied if you have any that do not draw 2mA.

The theory is sound as long as it does what it says it is supposed to do! The mobile version works and is a lot less risky but does not fit the loading gauge very well (too tall and the steps foul the bogies).