Reports & Discoverer :: Dynamically Displaying Current Value In Rows

where I have to display the value of current cell in next following cells.The table structure is as follows :

ttdate - date
individualplanid - varchar(10); - train number
sch_deptime - number(8); - scheduled departure time in milli seconds
sch_arrtime - number(8); - scheduled arrival time in milli seconds
stn - varchar(10); - station short name
dep_delay - number(8); - dep delay in milli seconds
arr_delay - number(8); - arr delay in milli seconds

The delay is filled continuously by application software continuously.I want to make a query where I want a calculated field which does the prediction of train arrival on coming stations. This shall be done as the delay + sch_deptime for all the next stations. Following is a dataset :

individualplanid sch_deptime sch_arrtime stn arr_delay dep_delay

BO646NULL57900000BVINULL80000
BO646NULL58140000KILENULL40000
BO646NULL58320000MDDNULL20000
BO646NULL58530000GMNNULLNULL
BO646NULL59160000ADHNULLNULL
BO646NULL59550000STCNULLNULL
BO646NULL59940000BANULLNULL
BO646NULL60540000DDRNULLNULL
BO646NULL61200000BCLNULLNULL
BO64661800000NULLCCG12000NULL
[code]....

The last column (EAT) is calculated one. It shall be like as the dep_delay is updated the EAT for the following records shall be sch_deptime + dep_ delay. I did was something like this. The calculated field is cum_depdelay which is only the delay ( not sch_deptime + dep_delay ).

select ttdate,individualplanid td,station,sch_deptime,sch_arrtime,act_depdelay,
sum(act_depdelay) over ( partition by individualplanid order by sch_deptime rows between current row and unbounded following ) c_depdelay
from logtime where ttdate='14-Mar-2011' and individualplanid='BO646' order by sch_deptime,sch_arrtime;
[code]...

how shall i proceed ?