Digitrax Zephyr - Low top speed

[Pacific Northern]

I recently upgraded my DCC from a basic Bachmann EZ command system to a Digitrax Zephry.

i am very disappointed with the top speed of the Digitrax unit. I checked the Zephry's setting and the top speed is set to the units max. Both DC and DCC engines are equally affected.

The digitrax unit's top speed is set correctly.

The top speed of the Digitrax is only about 2/3 of the Bachmann EZ Command. The Zephyr reaches top speed at setting 4 and does not increase speed through setting 5 or the max 6.

I have about 55' of mainline track on my layout. Would adding more feeders help? Is there anything I could try.

[Jim Banner]

The Zephyr is designed to apply 12 volts dc maximum to locomotive motors.  This is the NMRA recommended full speed voltage for H0.  You may find this somewhat slower than the top speeds when running single locomotives on Bachmann's E-Z Command as the maximum voltage it applies to motors is somewhat higher when lightly loaded.

Most of us are more interested in being able to run at scale speeds.  If you keep in mind that 60 miles per hour is 88 feet per second, and that 87.1 H0 feet equal almost exactly 1 real world foot, then a good conversion is 1 real foot per second equals 60 miles per hour in the H0 world.  One real foot per second train speed is about two H0 box cars per second passing a fixed point.  You can use this as a quick check on train speed:
1 box car per second = 30 mph
2 box cars per second = 60 mph
3 box cars per second = 90 mph
4 box cars per second = 120 mph.
Ideally, the box cars should be 40 footers but even if you run 50 footers, the estimate is still close.  This works in all scales and with real world trains as well.

If you want more accuracy, mark off 5 feet of track and use the stop watch function on your watch.  Time how long it takes for your train to travel 6 feet.  Then the speeds are:
6 feet in 1 second = 360 mph
6 feet in 2 seconds = 180 mph
6 feet in 3 seconds = 120 mph
6 feet in 4 seconds = 90 mph
6 feet in 4.5 seconds = 80 mph = track speed for passenger
6 feet in 5 seconds = 72 mph
6 feet in 6 seconds = 60 mph
6 feet in 7 seconds =  51 mph
6 feet in 7.2 seconds = 50 mph = track speed for freight
6 feet in 8 seconds =  45 mph
6 feet in 9 seconds = 40 mph
6 feet in 10 seconds = 36 mph
6 feet in 11 seconds = 33 mph
6 feet in 12 seconds = 30 mph = restricted speed
6 feet in 15 seconds = 24 mph
6 feet in 20 seconds = 18 mph
6 feet in 25 seconds = 14 mph
6 feet in 30 seconds = 12 mph
6 feet in 36 seconds = 10 mph = slow speed
6 feet in 45 seconds = 8 mph
6 feet in 60 seconds = 6 mph
6 feet in 72 seconds = 5 mph = switching speed
For in between values, divide the time in seconds to travel 6 feet into 360.  The answer is in miles per hour.  This works in H0 only!  Your railroad may use different speed definitions.

Jim

[jward]

some small notes of correction regarding the speed tables.

these rules are according to conrail/norac and also apply to norfolk southern and are paraphrased from conrail signal indication cards that employees are required to have in their posession....

30 mph is medium speed, not restricted. this is the usual speed limit for approach signal indications, as well as crossover moves between tracks. for those, the signal would display a "medium clear" indication.

longer switches allow for a "limited" speed which i've seen listed as either 40 or 45 mph. these crossovers using "high speed switches are usually #20, and the indication you get when using the crossover is called a "limited clear."

restricted speed is described as a speed at which the train can be stopped within half the range of vision, not to exceed 15 mph. the signal indication you'd get in this instance would be called "restricting" or in older rule books, a "call on" or "permissive" indication.

[Jim Banner]

Thanks, Jeffery.  There is also a table of allowed speeds versus track class versus service at this link:
http://en.wikipedia.org/wiki/Speed_limits_in_the_United_States_%28rail%29

Jim