Ichimusai's Place » underground

Train Drive Test

Ichimusai — Sun, 05 Feb 2012 09:56:12 +0000

After finishing up the last bits of the project to install coverage in the Stockholm underground Metro system there has now been a drive test conducted.

This is a short video showing some of the activities and some pictures from this more fun side of the job.

For the more technical people out there I can tell you that we are actually measuring several radio services:

Train communication radio

RAKEL – swedish blue light services radio
Busskom – Our own TETRA network
SplitZone – Our own new TETRA network that will in time replace Busskom
FM Broadcast – For public service, commercial stations as well and important messages to the public

We also had a visit from the mobile operator Tre that conducted drive test measurement on their 3G network with good results.

The test equipment consists of the following:

Laptop logging all the data
Doppler radar mounted under the train that gives us the trains movement as 400 clicks per meter. This is connected to a small PIC processor that calculates the current distance always that can be queried from the laptop when necessary to get the current distance.
Rhode & Scwarz ESPI test receiver, capable of measuring many frequencies at the same time, in this test we did 19 channels with 7-10 samples per second.
GPS for accurate time synchronization
Antennas for the various bands being measured
Signal generators for uplink signal
Amplifiers for the uplink signal to match the levels generated by the train radios
Test receivers at the base stations to receive the uplink signals and log them with the same time reference

Underground Stalagmites

Ichimusai — Thu, 04 Feb 2010 20:19:38 +0000

During tuesday night we took a test train out from Work to check the radio communications equipment in the tunnels of the blue line on the Stockholm metro. During these tests we found at one of the turning points these incredible stalagmites formed by water frozen to ice. This water drips from the ceiling of the tunnel and forms incredible shapes.

Today I believe they started melting again because the temperature has gone from sub-zero to just above now and just walking down the street is really a perilous business these days…

The photos below are not taken with my ordinary camera but with my work cam which is a Panasonic Lumix DMC-LX3:

Odenplan Metro Station

Ichimusai — Sat, 28 Mar 2009 12:09:49 +0000

Odenplan metro station in the heart of the green line that is the oldest metro line in Stockholm is one of the most busy stations. During the peak-hours the traffic runs every three minutes or even faster some times, the trains are virtually tail to nose as they pass by.

Odenplan metro station. This shot was inspired by a similar shot from Stina's blog!

The above photo was inspired by Stina’s similar photograph of the same station.

I kind of like these older stations in the metro they are very fifties in a way and they have a very special feeling to them.

3 minute traffic and oncoming trains all the time...

Check out Hötorget, S:t Eriksplan and Odenplan.

Kungsträdgården metro station

Ichimusai — Wed, 04 Mar 2009 21:13:41 +0000

Kungsträdgården is one of the most remarkable underground metro stations in the Stockholm Metro system. It is the south end point of the blue line and from here it goes to both Akalla and Hjulsta. The Kungsträdgården stop is just one stop south of the central station, T-Centralen.

The station is located in the bedrock under Jakobsgatan, Jakobs church and Arsenalsgatan through the Kungsträdgården park area. The platform is about 35 meters below ground and can be reached through the entrances placed at Regeringsgatan/Gallerian or Arsenalsgatan. There are two tracks here and trains going to Hjulsta and Akalla always starts from the same side. The Akalla line sometimes have to cross tracks with south going trains and this causes frequent delays. Both tracks may change sides to left hand side traffic north of the platform since the whole metro system makes use of left hand side driving of the trains.

The artist who did the fabulous work in this station is called Ulrik Samuelson and he has found inspiration from the palaces around kungsträdgården. The red man here is a war god that used to sit on Riddarhusets (house of knights) roof there are also male and female torsos and many many other beautiful things to see here. If you are visiting Stockholm don’t miss this station!

The Warrior God, or as he is well known as "the red guy"

One of the installations on either side of the entrance from Arsenalsgatan

Entrance from Arsenalsgatan showing the decorated roof, the floor and the installations on either side of the walkway.