TIU - When would I need two?

if you follow the rules like in Barry's book, when you have more track than one TIU can connect to reliably, you need another. Remember with AC power, you have all 4 channels to utilize.

An engine yard or places where large number of engines are on powered tracks at the same time, can change the amount of track statement I made.

I run multiple layouts, so it multiplies my needs by those same rules.

Well....one for a spare obviously. And then the question of how many fixed and variable outputs you need. You can get up to 4 fixed from one TIU. But only 2 variable. And finally, I like lots of electrical blocks. One TIU can support 4 blocks, 2 var and 2, 3 or 4 fixed. If a derailment or any gremlin happens to short the track, only that block is affected. The problem is isolated, easier to find and limited in scope to that block. The "easier to find" part is right up my alley. 

All of this is beyond the obvious need to run multiple trains, especially energy-sucking lit-up passenger trains. Multiple blocks allow you spread those current demands around, sharing the current drain. Running passive mode eliminates this value of multiple blocks. But I know nothing about passive mode since I never tried it.

I run 12 blocks on a 17' square island layout (that one day will actually use all 12 blocks...but **** that day seems far away sometimes). So far I haven't had any reason to regret designing a lot of blocks into the layout. But I'm no expert and the layout is far from complete. So we will see what it has in store for me.

Don

Don Merz 070317 posted:

….One TIU can support 4 blocks, 2 var and 2, 3 or 4 fixed.

….Multiple blocks allow you spread those current demands around, sharing the current drain. Running passive mode eliminates this value of multiple blocks. But I know nothing about passive mode since I never tried it.

I run 12 blocks on a 17' square island layout (that one day will actually use all 12 blocks...but **** that day seems far away sometimes). So far I haven't had any reason to regret designing a lot of blocks into the layout. But I'm no expert and the layout is far from complete. So we will see what it has in store for me.

Don

 

 

The TIU can only support four blocks? I think you mean channels or types of separate blocks?

I believe the biggest factor with O gauge three rail track, is usually the number of track joints. Each joint has a loss of power transfer and that ultimately determines just how you connect your layout. So we have to consider what track you're talking about first. How the track is connected together. Finally, how the power is connected from the transformer all the way to the rails (size of wire, number and type of connections, etc.).

 Another factor considered for TIU channels is how much draw each train will have. If you're running large consists pulling pass cars with real light bulbs inside, you need more power. The discussion of blocks is all about delivering that extra power if needed, and/or turning it off where you don't.

Thank you gentlemen.

I wiill be using Gargrave Track.  The yard / engine service  area is 12 x 6 and main train room (two rooms divided by a wall) is around 10 x 16. 

Seems a second TIU is in order. Thanks again.

Paul 

I have eight different “loops” so I have 2, 4 loops per TIU.  Might be overkill, but I don’t think I could run all 8 with just 1.  With two engines per loop, and smoke units, I don’t think 1 output could handle it.

Tony H posted:

I have eight different “loops” so I have 2, 4 loops per TIU.  Might be overkill, but I don’t think I could run all 8 with just 1.  With two engines per loop, and smoke units, I don’t think 1 output could handle it.

 

I've run 5 MTH engines with smoke on a single TIU channel. Not everyone could probably do that. It depends on the actual power getting to the rails. My O scale layout inside is fairly level too. My G scale has the voltage turned up higher to help. The O scale 2 rail has Lionel PH180 bricks.

 BTW I have 7 loops of track at about 75' or more per TIU channel.

Engineer-Joe posted:

Tony H posted:

I have eight different “loops” so I have 2, 4 loops per TIU.  Might be overkill, but I don’t think I could run all 8 with just 1.  With two engines per loop, and smoke units, I don’t think 1 output could handle it.

 

I've run 5 MTH engines with smoke on a single TIU channel. Not everyone could probably do that. It depends on the actual power getting to the rails. My O scale layout inside is fairly level too. My G scale has the voltage turned up higher to help. The O scale 2 rail has Lionel PH180 bricks.

 BTW I have 7 loops of track at about 75' or more per TIU channel.

Do you run in passive mode?

Tony H posted

Do you run in passive mode?

 

No