I'm building a temporary layout for my sons and don't want the trains to run full speed down the 4% grade. The kids can't reverse the trains, but the uphill is steep. Any suggestions from you electrical geniuses today?
No, don't even think about telling me to use DCC and setting the max speed lower. We're using old DC trains that I won't be too heartbroken over when they break them.
Thanks in advance.
Eddie and Kevin's Daddy.
HEdward:
A simple way to do this would be to make the downhill stretch a separate block and include a resistor in the power feed to this block. A heavy duty resistor (a few watts) should do. You would have to experiment with the ohms to give the desired speed. Of course, the uphill speed would also be affected but since the kids can't reverse that may not be a concern..
Joe
If you're running a modern can-motored loco, 5 - 10 ohms won't do much to slow it down. You might need a good bit more.
I run both can motors and open-frames. There's one place where I installed a 10 ohm resistor to decelerate locos before an auto-stop section. The open frames slow nicely. The can motors hardly even notice. I haven't experimented to find out what needs to be done to slow a can motor, so that's a question I can't answer.
If you might ever want to run a train upgrade, you could bypass the resistor with a diode.
Chuck (modeling Central Japan in September, 1964 - analog DC, MZL system)
HEdward wrote:Rather than running wiring to the two blocks from the control area, I'll merely jumper the resistor across the gap.
I was going to suggest putting a SPST switch around that resistor to make it easy to bypass the resistor and give the track full power.
Another solution that works regardless of motor type is a diode string instead of a resistor. Each diode typically drops 0.65 volts. Add diodes in series to get the desired voltage drop. A typical diode curent rating of 1 amp, 25 PIV is sufficient for small layouts. For bidirectional operation, at least one diode pointing the opposite direction and in parallel with the primary string is needed. Diodes are cheaper and easier to find than high wattage resistors.
Just a thought
Fred W
Texas Zepher wrote: HEdward wrote:Rather than running wiring to the two blocks from the control area, I'll merely jumper the resistor across the gap.Any chance that a train might some time want to go UP that hill in the opposite direction? I was going to suggest putting a SPST switch around that resistor to make it easy to bypass the resistor and give the track full power.
I'm blocking the reversing switch on the power packs. At 2 1/2 years old, I'm giving them more control than their age would normally dictate. This is all until the ancient O scale loco can be replaced. I'm hoping to get a Polar Expresstm set for them later this year. Meanwhile, double track figure eight, trains running in opposite directions, controlled from opposite sides, going up on the outside track and down on the inner, nearly no scenery. I want them to run it, but as simplistically and safely as possible without becoming merely an animated display.
Thanks for all the input. Now if the local rotshack(did you know the stock was at 39 when I left in 2002 and is now under 13)still has parts, I'll be in business.
Radio Shack also makes a 25W potentiometer (designed for stereo systems) that you can use. Nice thing about it is it's adjustable, so you can set it to provide enough power to go down grade without derailing no matter how fast they go.
Of course, you could also just run the entire layout's power thru the pot, so that even if they turn the power pack up to 100% they're only getting say 50-60% power to run the trains - set it so it's just enough to get the train up the grade - rather than letting them run trains full blast on parts of the layout and just trying to control the downhill section.
HEdward wrote:We're using old DC trains that I won't be too heartbroken over when they break them.
In that case it seems to me that you could make the grade a separate electrical block and reduce the voltage to that section with a couple resistors.
WaxonWaxov wrote: HEdward wrote:We're using old DC trains that I won't be too heartbroken over when they break them. In that case it seems to me that you could make the grade a separate electrical block and reduce the voltage to that section with a couple resistors.
LMAO!!! Went to RadidioSnack and got 10W 10ohm resistors. Suddenly their stock shoots up! Went I resigned their employ in 2002, the stock went from 39 to 9. Last year I bought a phone battery and the stock bumped up that week as well, only to fall back again. So next year, I'll let you guys know when I'm plotting a purchase there.
I haven't laid the track yet, needed four 4" pieces I swore the old layout used at least two. Actually, one of my UP locos has a fly wheel. Trains won't be long and I'll be testing this ALOT!