BLI Rolling Thunder concept: compatiblity with RailPro?

[jimw]

I haven't seen this  system in use, but it looks enticing to those who might wish for "big" sound from our tiny speakers.  I am curious whether anyone has experience with this or similar radio sound relay to a large speaker system?  Could RailPro's radio capability be used to drive a speaker through a signal relay/amplifier?  It obviously would take some tweaking of the LM-xS' output to either utilize the module's internal radio transmitter, or installation of a 'jury-rigged' radio relay.  Sadly, my electronics memories are not up to the task, but the concept seems ideal to the RailPro format.

Just a curious idea:  any thoughts?

Jim Wilkens

[G8B4Life]

I haven't seen this system in use but I have seen the promo for it; or should I say the promo demonstrating just one loco using it (does it work with more than one loco at a time?)  For what it's worth I'm not a big fan of the under the table system. Our models could sound better without resorting to systems like this if manufacturers hired sound engineers to design the sound path and baffling inside our models.

Back to the subject, I'm sure it could be done however probably not by RE, BLI does have a patent on Rolling Thunder. I don't know what part is patented but it probably encompasses transmitting sound via radio transmission. That said the transmitter inside an LM could do what you say, that is probably not directly to a Rolling Thunder system but the same concept though I'm not sure I'd like that given the amount of radio traffic it has to contend with already. Another way could be to design a transmitter board that takes the speaker outputs and transmits them to a receiver hooked up to an amp but then your trying to cram another transmitter into a loco shell and two transmitters in such close proximity may not work that well.

- Tim

[jimw]

Tim: 

Thanks for your thoughtful reply.  Your reservations about this idea reflect my own, but I was interested enough to inquire. Since most of my motive power has little extra space, I will be ordering some I-phone 4 speakers to see whether the sound is better than the 28mm speaker I have used.  I really don't see any other way to get baffles in the tight SD7 shell.

JimW

[G8B4Life]

Jim,

I think you will be pleased with the iPhone speaker, they sound great with good volume; might be something to do with the fact they were designed by some very smart people that would have included sound engineers 

An SD7 eh, not knowing the brand you might have to grind some of the weight away to fit the iPhone speaker in, they are quite longish.

I wonder how many US enthusiasts know the actual story behind the SD7?

- Tim

[Josephbw]

On the face of it, the BLI system sounds like a good idea. But I will bet that after 10 minutes of listening to bass reverberations, you will be ready to turn it way down or off. I installed an I phone speaker in one engine that was so loud I had to turn the sound way down as I was starting to get a headache. If you are hearing impaired though, it might be a blessing. 

Joe

[jimw]

Tim:  That last bit about SD7 history is tantalizing.  I had understood the rationale for 6 axle power was to decrease per-axle track load and increase tractive force.  Somehow that seems a little too obvious, so I'll bite:  what's the secret?

Jim W

[jimw]

Joe:  Thanks for your thoughts.  Looks like iPhone 4 speakers are the ticket.  I know Bill sells them, so I'll send him an order.  Thankfully my hearing loss has been limited to the high-pitch (read: female) end of the spectrum!  (Boy,  I hope my wife doesn't read this!)

Jim   

[G8B4Life]

Jim,

Your rationale is 100% correct but as you say that's the obvious part, the "secret", seeing it doesn't seem that well known is this (I'll try to keep it short, it is a good but lengthy history the whole story):

The very first EMD C-C bogie (truck) that was the genesis of the SD7, which in itself was the genesis of the whole SD line, was not destined for the US market. It was designed by EMD (after much protest from EMD apparently) at the request of the then Victorian Railways here for our first mainline DE locomotive, the ML-2.

However, as it turns out we did not end up with it. Back in those days the mantra here was still very much "buy British" so the US dollar allocation from the Government ended up not being enough for all the parts from EMD for all the locos; A decision was made that the bogies could be made here and to get from EMD those things that couldn't be made locally, such as the engine and traction motors etc.

This left EMD with a pair of very good very usable C-C bogies that had cost time and money to develop doing nothing so as history would have it they streched a GP7 and made the very first model in the SD line, the SD7.

So the part that was genesis of the SD7 and the SD line in general, the three axle three motor bogie was an export item designed at the request from, and for a railway in Australia.
 
- Tim

[Alan]

Fascinating.

I assume they had to flip them over for use in northern latitudes. Or is it the wheels spin the opposite direction? 

[jimw]

Tim:

A photo (but not the interesting embryology) of SP1518 (currently at the Illinois Railway Museum) is on Wikipedia.  The article states it is the first of its class, and hints that it is slightly different from its successors.  Perhaps an update to the article could be of interest?  I would never have guessed your answer!

Jim W

[G8B4Life]

Alan,

No, they were orientated the correct way for the north so they could test them, we would have flipped them over when they got here.    The test train would be great modelling for anyone modelling the Chicago area circa 1949. Imagine if you will, in order, a flat car fitted with railings and a hut sporting the new bogies, an F3 (traction motors disconnected and power fed to the bogies under the flat car) and a caboose barrelling down the tracks at high speed. Must have been a strange sight.

Jim,

It's not common knowledge, at least to those in the US as no one's published a comprehensive history of the SD7 or the SD line as a whole. This could be because the same level of history is not there for the SD7 (and in general a large number of US diesels) as there is for loco's here simply because of the sales method employed; By and large by that time US builders developed the locomotives by themselves and then offered them in a catalogue for all and sundry to purchase where as railways here, being government owned until recently (1990's) had to put out tenders and builders designed something to fulfill that tender.

- Tim

[jimw]

Tim

Your history of the SD7 verifies the adage "truth is stranger than fiction."  That would be a really nifty scene to model the C-C powered flatcar/F3-unit/caboose test scene.  Are you aware of any photographs or movies of the test units?

Jim W

[G8B4Life]

Jim,

I know of exactly one photo that shows the whole train; from a distance so it's not that good for studying detail. I can't rightly remember where I saw it but I think it's in a book I have. I know of three other photos that show partial views of the train. These are in another book I have which I do know where it is.

- Tim