Reliable lighting around the clock

At the Meien­dor­fer Weg U1 stop in Ham­burg, intel­li­gent con­trol tech­nol­o­gy ensures con­tin­u­ous light­ing. The pilot project was ini­ti­at­ed as part of the bar­ri­er-free expan­sion of the sta­tion. It impres­sive­ly demon­strates the pos­si­bil­i­ties and advan­tages that the use of demand-based light­ing con­trol opens up for oper­a­tors and passengers.
With a route length of almost 56 kilo­me­ters, the U1 is the longest of Ham­burg’s sub­way lines. The blue line con­nects Norder­st­edt with down­town Ham­burg and then runs to Volks­dorf, where it splits in two direc­tions to Ohlst­edt and Großhans­dorf. Almost all of the 47 U1 stops are now bar­ri­er-free. This is because, with its large-scale “Lift Pro­gram,” Ham­burg­er Hochbahn has been work­ing at tur­bo speed for sev­er­al years to pro­vide com­fort­able, bar­ri­er-free access for all of Ham­burg’s sub­way stops: with one ele­va­tor per plat­form, (par­tial­ly) ele­vat­ed plat­forms for lev­el-equal­ized board­ing and alight­ing, and a tac­tile ori­en­ta­tion sys­tem for the blind and visu­al­ly impaired. The Meien­dor­fer Weg stop, for exam­ple, also received a thor­ough facelift at the end of 2018. Opened in 1925 and pro­vid­ed with a new entrance in the 1950s and expand­ed to include a sales pavil­ion, the stop is now used by around 7,000 pas­sen­gers every day.
 

Intelligent complete solution

Just as con­ve­nient as the bar­ri­er-free access is the light­ing, which was com­plete­ly renewed as part of the refur­bish­ment. As a long-stand­ing part­ner of Ham­burg­er Hochbahn, the lumi­naire man­u­fac­tur­er NORKA imple­ment­ed the new light­ing con­cept and, togeth­er with its part­ner com­pa­ny NORKA Automa­tion, which spe­cial­izes in con­trol intel­li­gence, devel­oped a high­ly com­plex com­plete solu­tion tai­lored to the spe­cial require­ments as a pilot project.
NORKA ERFURT LED lumi­naires in var­i­ous designs ensure good vis­i­bil­i­ty and safe ori­en­ta­tion in the build­ing as well as on the cov­ered plat­form. They are inte­grat­ed into a sup­port tube sys­tem that also accom­mo­dates oth­er tech­nol­o­gy such as loud­speak­ers and cable rout­ing. On the cen­tral plat­form, two of these sys­tems are used along the tracks. In them, one lumi­naire with wide-beam light char­ac­ter­is­tics fol­lows the oth­er at inter­vals of around three meters. The swivel­ing pro­tec­tive tube and the inter­nal alu­minum reflec­tor pro­duce a light dis­tri­b­u­tion that pre­cise­ly match­es the plat­form geom­e­try. This means that all stan­dard spec­i­fi­ca­tions for illu­mi­nance, uni­for­mi­ty and absence of glare are reli­ably met in both lon­gi­tu­di­nal and trans­verse direc­tions. In the two tick­et halls and in the cor­ri­dors, in the stair­case area and in the wait­ing area, the lumi­naires with room-radi­at­ing light dis­tri­b­u­tion ensure pleas­ant, uni­form brightness.
 

Fully automatic lighting control

Even though a pas­sen­ger spends an aver­age of only sev­en min­utes in the sta­tion, he or she should feel com­fort­able and safe dur­ing this time. The XARA® Pro­fes­sion­al light­ing con­trol sys­tem ensures that this always func­tions smooth­ly — espe­cial­ly in the event of a mal­func­tion. The heart and at the same time brain of the light­ing sys­tem con­trols the lumi­naires ful­ly auto­mat­i­cal­ly: It watch­es over the dif­fer­ent light­ing areas and con­stant­ly reg­u­lates the amount of light depend­ing on the day­light inten­si­ty. It detects and reacts to move­ment, leav­ing no one in the dark for safe­ty rea­sons. It mon­i­tors the emer­gency lumi­naires, diag­noses pos­si­ble defects and ensures that, in the event of a fault, the reduc­tion in light in the affect­ed area is com­pen­sat­ed. It records ener­gy con­sump­tion — and can do much more.
This func­tion­al diver­si­ty is achieved with a pro­gram­ma­ble log­ic con­troller (PLC) that is oth­er­wise used to con­trol indus­tri­al machin­ery It switch­es and reg­u­lates the light in the stop from a con­trol cab­i­net. The PLC sends its com­mands via DALI (Dig­i­tal Address­able Light­ing Inter­face) to a total of 60 lumi­naires. The input for the light­ing con­trol is pro­vid­ed by light sen­sors as well as infrared and radar motion sen­sors locat­ed in defined light­ing areas, such as the counter hall, stairs and cov­ered plat­form. Light­ing func­tions are assigned to the var­i­ous areas and are acti­vat­ed and con­trolled depend­ing on the oper­at­ing sta­tus of the sta­tion as well as from the mea­sure­ment signals.
 

Demand-driven light around the clock

In nor­mal day­time oper­a­tion, the light­ing on the plat­form is con­trolled accord­ing to day­light and in the counter hall accord­ing to day­light and move­ment. If the min­i­mum illu­mi­nance lev­els of a con­stant 100 lux on the plat­form and a basic lev­el of 60 lux in the build­ing are under­shot, e.g. dur­ing thun­der­clouds or on gray win­ter days, the con­trol sys­tem ensures that the light lev­el is increased accord­ing­ly. If the motion sen­sors installed in the build­ing detect move­ment, the lumi­naires here are gen­tly dimmed up to 150 lux. When the last pas­sen­gers leave the build­ing, the bright­ness is main­tained for anoth­er 15 min­utes and then slow­ly dimmed down to 100 lux. After a fur­ther 15 min­utes with­out motion detec­tion, the dim­ming returns to the basic lev­el of 60 lux. This does not apply to the stair­case, where the illu­mi­nance is a con­stant 150 lux for safe­ty reasons.
A twi­light switch func­tion is imple­ment­ed in the con­trol sys­tem, which tells the sys­tem at which bright­ness lev­el it should switch to night mode. With an illu­mi­nance of at least 100 lux, the sta­tion remains pleas­ant­ly bright even in night mode. In the twi­light phase, an addi­tion­al increase in the light lev­el of around 50 lux pro­vides the train dri­ver with a bet­ter overview of the sit­u­a­tion on the plat­form and increas­es pas­sen­ger safe­ty. In the dark, a cir­cuit break­er is used to switch on the non-dim­ma­ble lumi­naires of the infor­ma­tion and path light­ing in the vicin­i­ty of the stop.
Dur­ing off-peak hours, i.e. between the last train at night and the first in the morn­ing, there is min­i­mum light­ing on the plat­form, which is rough­ly equiv­a­lent to the bright­ness on a full moon night.
 

Reliable safety

In addi­tion to record­ing the ener­gy con­sump­tion of each indi­vid­ual lumi­naire, the light­ing con­trol sys­tem con­tin­u­ous­ly per­forms self-diag­no­sis and inter­ro­gates any faults with­in the lumi­naires, the con­trol gear or in the com­mu­ni­ca­tion via the DALI bus at reg­u­lar inter­vals. In addi­tion, the pow­er sup­ply and sen­sor sig­nals are mon­i­tored. If a fault is detect­ed, the con­trol sys­tem gen­er­ates a fault mes­sage and dis­plays it imme­di­ate­ly on the local con­trol pan­el. At the same time, it sends the cor­re­spond­ing mes­sage sig­nals to the con­trol cen­ter and, if pos­si­ble, ini­ti­ates a fault com­pen­sa­tion sce­nario. If, for exam­ple, there is a lumi­naire fail­ure, the con­trol sys­tem com­pen­sates for this by increas­ing the dim­ming lev­el of the sur­round­ing lumi­naires until the min­i­mum illu­mi­nance in the affect­ed area is reached again.
In this way, the high­ly com­plex light­ing con­trol sys­tem at the Meien­dor­fer Weg sub­way stop offers oper­a­tors a high lev­el of safe­ty. They can rely on the light­ing to func­tion reli­ably even in the event of a mal­func­tion. But pas­sen­gers also ben­e­fit from safe and pleas­ant light that is tai­lored pre­cise­ly to their needs.