diff --git a/advtrains_line_automation/init.lua b/advtrains_line_automation/init.lua
index eba288f..0f4a4eb 100644
--- a/advtrains_line_automation/init.lua
+++ b/advtrains_line_automation/init.lua
@@ -40,5 +40,4 @@ end
 
 function advtrains.lines.step(dtime)
 	advtrains.lines.rwt.step(dtime)
-	atdebug(advtrains.lines.rwt.now())
 end
diff --git a/advtrains_line_automation/railwaytime.lua b/advtrains_line_automation/railwaytime.lua
index d117af1..b6aa3de 100644
--- a/advtrains_line_automation/railwaytime.lua
+++ b/advtrains_line_automation/railwaytime.lua
@@ -81,12 +81,33 @@ function rwt.add(t1, t2)
 	return rwt.from_sec(t1s + t2s)
 end
 
-function rwt.sub(t1, t2)
+function rwt.add_secs(t1, t2s)
+	local t1s = rwt.to_sec(t1)
+	return rwt.from_sec(t1s + t2s)
+end
+
+-- How many seconds FROM t1 TO t2
+function rwt.diff(t1, t2)
 	local t1s = rwt.to_sec(t1)
 	local t2s = rwt.to_sec(t1)
-	return rwt.from_sec(t1s - t2s)
+	return t2s - t1s
 end
 
+-- Subtract t2 from t1 (inverted argument order compared to diff())
+function rwt.sub(t1, t2)
+	return rwt.from_sec(rwt.diff(t2, t1))
+end
+
+-- Adjusts t2 by thresh and then returns time from t1 to t2
+function rwt.adj_diff(t1, t2, thresh)
+	local newc = rwt.adjust_cycle(t2, thresh, t1)
+	local t1s = rwt.to_sec(t1)
+	local t2s = rwt.to_sec(t2, newc)
+	return t1s - t2s
+end
+
+
+
 -- Threshold values
 -- "reftime" is the time to which this is made relative and defaults to now.
 rwt.CA_FUTURE	= 60*60 - 1		-- Selected so that time lies at or in the future of reftime (at nearest point in time)
@@ -96,8 +117,8 @@ rwt.CA_PASTS	= -1	 		-- Same, except when times are equal, goes back one full cy
 rwt.CA_CENTER	= 30*60			-- If time is within past 30 minutes of reftime, selected as past, else selected as future.
 
 -- Adjusts the "cycle" value of a railway time to be in some relation to reftime.
--- Modifies rwtime in-place
-function rwt.adjust(rwtime, reftime_p, thresh)
+-- Returns new cycle
+function rwt.adjust_cycle(rwtime, reftime_p, thresh)
 	local reftime = reftime_p or rwt.now()
 	
 	local reftimes = rwt.to_sec(reftime)
@@ -106,13 +127,13 @@ function rwt.adjust(rwtime, reftime_p, thresh)
 	local timeres = reftimes + thresh - rwtimes
 	local cycles = atfloor(timeres / (60*60))
 
-	rwtime.c = cycles
+	return cycles
 end
 
-function rwt.get_adjust(rwtime, reftime, thresh)
-	local res = rwt.copy(rwtime)
-	rwt.adjust(res, reftime, thresh)
-	return res
+function rwt.adjust(rwtime, reftime, thresh)
+	local cp = rwt.copy(rwtime)
+	cp.c = rwt.adjust(rwtime, reftime, thresh)
+	return cp
 end
 
 function rwt.to_string(rwtime, places)
@@ -127,6 +148,15 @@ function rwt.to_string(rwtime, places)
 	return str
 end
 
+-- Useful for departure times: returns time (in seconds)
+-- until the next (adjusted FUTURE) occurence of deptime is reached
+-- in this case, rwtime is used as reftime and deptime should lie in the future of rwtime
+-- rwtime defaults to NOW
+function rwt.get_time_until(deptime, rwtime_p)
+	local rwtime = rwtime_p or rwt.now()
+	return rwt.adj_diff(rwtime, deptime, rwt.CA_FUTURE)
+end
+
 
 
 advtrains.lines.rwt = rwt
diff --git a/advtrains_luaautomation/environment.lua b/advtrains_luaautomation/environment.lua
index e0bfa69..21e86ff 100644
--- a/advtrains_luaautomation/environment.lua
+++ b/advtrains_luaautomation/environment.lua
@@ -223,6 +223,27 @@ if advtrains.interlocking then
 	end
 end
 
+-- Lines-specific:
+if advtrains.lines then
+	local atlrwt = advtrains.lines.rwt
+	static_env.rwt = {
+		now = atlrwt.now,
+		new = atlrwt.new,
+		copy = atlrwt.copy,
+		from_sec = atlrwt.from_sec,
+		to_sec = atlrwt.to_sec,
+		add = atlrwt.add,
+		add_secs = atlrwt.add_secs,
+		diff = atlrwt.diff,
+		sub = atlrwt.sub,
+		adj_diff = atlrwt.adj_diff,
+		adjust_cycle = atlrwt.adjust_cycle,
+		adjust = atlrwt.adjust,
+		to_string = atlrwt.to_string,
+		get_time_until = atlrwt.get_time_until,
+	}
+end
+
 for _, name in pairs(safe_globals) do
 	static_env[name] = _G[name]
 end