603 replies to this topic

[Fistach]

lightningtiger, on 19 June 2010 - 01:11 AM, said:

So logic would then say more cars the more likely it will stay on the tracks.
What if some weight was added to the engine, to use gravity as downward force on to the track. But it would have to be low on the chassis so not to topple over the engine when going around curves. I'll try it when i can get my hands on this train.
Keep on bricking everyone !

it doesn't matter if the number of cars is 4 or 5. What matters is what's train's speed and how high it's centre of gravity is. You can increase the speed if you lower the centre of gravity on ALL cars and engines. It's simple physics!

[lightningtiger]

Fistach, on 19 June 2010 - 12:05 PM, said:

it doesn't matter if the number of cars is 4 or 5. What matters is what's train's speed and how high it's centre of gravity is. You can increase the speed if you lower the centre of gravity on ALL cars and engines. It's simple physics!

Isn't that what I said, the more weight above a given point on the engine's body would mean a greater chance of a derailment, so weight below same point odds on derailment are reduced.
Just like a two storey building is more stable in strong winds than 100 storey one.
Keep on bricking !

[hoeij]

Dyson2972, on 19 June 2010 - 01:02 AM, said:

I did some testing at what speed does 7938 derail on a curve:

The engine by itself will derail on a curve at a speed of 5.

An engine and two cars will derail at a speed of 6.

An engine and three cars will derail at a speed of 6.

An engine and four cars will derail at the top speed of 7 (most of the time).

- Patrick

Thanks for the info,  this looks fairly similar to the previous passenger train, the only difference being
that the engine by itself does not derail on setting 5 due to its exceptionally low center of gravity
(but it does derail in setting 7).  The useful settings for the 5-car train are 3,4,5  (or 4,5,6 when I use
the other motor, the two RC motors that I have are not equally fast).  Below that, the motor is struggling,
while above that, you get to do some repairs.

To make the train easier to use, I've been considering replacing one of the 6 batteries by a dummy.  That
reduces the voltage to 7.5V max (for 5 regular batteries) or 6V max (for 5 rechargeable batteries, which is
what I use).  I haven't tested this, but I suspect that the RC mechanism will still work even when the
batteries supply only 6V, and that this should be enough to prevent derailings  (the idea is to use the
train at a train show and let kids run it...).

[MojoLego]

There are some new hi-res photos of the Public Transport set (8404) over in the Town forum:

http://www.eurobrick...c=32210&st=2130

The light rail cars do indeed use the small train wheels.  I assume it will fit L gauge track.

Also, for those of you in the U.S., TRU has listed the 2010 train sets.

Rob