diff --git a/src/operators/arrange.rs b/src/operators/arrange.rs
index 5f2ffa3a38..cb5b685878 100644
--- a/src/operators/arrange.rs
+++ b/src/operators/arrange.rs
@@ -50,7 +50,7 @@ pub struct TraceWriter<K, V, T, R, Tr>
 where T: Lattice+Ord+Clone+'static, Tr: Trace<K,V,T,R>, Tr::Batch: Batch<K,V,T,R> {
     phantom: ::std::marker::PhantomData<(K, V, R)>,
     trace: Weak<RefCell<TraceBox<K, V, T, R, Tr>>>,
-    queues: Rc<RefCell<(Vec<T>,Vec<Weak<RefCell<VecDeque<(Vec<T>, Option<(T, Tr::Batch)>)>>>>)>>,
+    queues: Rc<RefCell<(Vec<T>,Vec<TraceAgentQueueWriter<K,V,T,R,Tr>>)>>,
 }
 
 impl<K, V, T, R, Tr> TraceWriter<K, V, T, R, Tr>
@@ -63,8 +63,9 @@ where T: Lattice+Ord+Clone+'static, Tr: Trace<K,V,T,R>, Tr::Batch: Batch<K,V,T,R
         let mut borrow = self.queues.borrow_mut();
         borrow.0 = frontier.to_vec();
         for queue in borrow.1.iter_mut() {
-            if let Some(mut queue) = queue.upgrade() {
-                queue.borrow_mut().push_back((frontier.to_vec(), data.clone()));
+            if let Some(pair) = queue.upgrade() {
+                pair.1.borrow_mut().push_back((frontier.to_vec(), data.clone()));
+                pair.0.activate();
             }
         }
         borrow.1.retain(|w| w.upgrade().is_some());
@@ -97,14 +98,19 @@ where T: Lattice+Ord+Clone+'static, Tr: Trace<K,V,T,R>, Tr::Batch: Batch<K,V,T,R
 
         let mut borrow = self.queues.borrow_mut();
         for queue in borrow.1.iter_mut() {
-            queue.upgrade().map(|queue| {
-                queue.borrow_mut().push_back((Vec::new(), None));
+            queue.upgrade().map(|pair| {
+                pair.1.borrow_mut().push_back((Vec::new(), None));
+                pair.0.activate();
             });
         }
         borrow.1.retain(|w| w.upgrade().is_some());
     }
 }
 
+use timely::scheduling::Activator;
+// Short names for strongly and weakly owned activators and shared queues.
+type TraceAgentQueueReader<K,V,T,R,Tr> = Rc<(Activator, RefCell<VecDeque<(Vec<T>, Option<(T, <Tr as TraceReader<K,V,T,R>>::Batch)>)>>)>;
+type TraceAgentQueueWriter<K,V,T,R,Tr> = Weak<(Activator, RefCell<VecDeque<(Vec<T>, Option<(T, <Tr as TraceReader<K,V,T,R>>::Batch)>)>>)>;
 
 /// A `TraceReader` wrapper which can be imported into other dataflows.
 ///
@@ -114,7 +120,7 @@ pub struct TraceAgent<K, V, T, R, Tr>
 where T: Lattice+Ord+Clone+'static, Tr: TraceReader<K,V,T,R> {
     phantom: ::std::marker::PhantomData<(K, V, R)>,
     trace: Rc<RefCell<TraceBox<K, V, T, R, Tr>>>,
-    queues: Weak<RefCell<(Vec<T>,Vec<Weak<RefCell<VecDeque<(Vec<T>, Option<(T, Tr::Batch)>)>>>>)>>,
+    queues: Weak<RefCell<(Vec<T>,Vec<TraceAgentQueueWriter<K,V,T,R,Tr>>)>>,
     advance: Vec<T>,
     through: Vec<T>,
 }
@@ -173,7 +179,7 @@ where T: Timestamp+Lattice, Tr: TraceReader<K,V,T,R> {
     ///
     /// The queue will be immediately populated with existing historical batches from the trace, and until the reference
     /// is dropped the queue will receive new batches as produced by the source `arrange` operator.
-    pub fn new_listener(&mut self) -> Rc<RefCell<VecDeque<(Vec<T>, Option<(T, <Tr as TraceReader<K,V,T,R>>::Batch)>)>>> where T: Default {
+    pub fn new_listener(&mut self, activator: Activator) -> TraceAgentQueueReader<K,V,T,R,Tr> where T: Default {
 
         // create a new queue for progress and batch information.
         let mut new_queue = VecDeque::new();
@@ -183,18 +189,19 @@ where T: Timestamp+Lattice, Tr: TraceReader<K,V,T,R> {
             new_queue.push_back((vec![T::default()], Some((T::default(), batch.clone()))));
         });
 
-        let reference = Rc::new(RefCell::new(new_queue));
+        let reference = Rc::new((activator, RefCell::new(new_queue)));
 
         // wraps the queue in a ref-counted ref cell and enqueue/return it.
         if let Some(queue) = self.queues.upgrade() {
             let mut borrow = queue.borrow_mut();
-            reference.borrow_mut().push_back((borrow.0.clone(), None));
+            reference.1.borrow_mut().push_back((borrow.0.clone(), None));
             borrow.1.push(Rc::downgrade(&reference));
         }
         else {
             // if the trace is closed, send a final signal.
-            reference.borrow_mut().push_back((Vec::new(), None));
+            reference.1.borrow_mut().push_back((Vec::new(), None));
         }
+        reference.0.activate();
 
         reference
     }
@@ -263,16 +270,19 @@ where T: Lattice+Ord+Clone+'static, Tr: TraceReader<K,V,T,R> {
     /// ```
     pub fn import<G: Scope<Timestamp=T>>(&mut self, scope: &G) -> Arranged<G, K, V, R, TraceAgent<K, V, T, R, Tr>> where T: Timestamp {
 
-        let queue = self.new_listener();
+        let trace = self.clone();
 
-        let collection = source(scope, "ArrangedSource", move |capability, _info| {
+        let stream = source(scope, "ArrangedSource", move |capability, info| {
+
+            let activator = scope.activator_for(&info.address[..]);
+            let queue = self.new_listener(activator);
 
             // capabilities the source maintains.
             let mut capabilities = vec![capability];
 
             move |output| {
 
-                let mut borrow = queue.borrow_mut();
+                let mut borrow = queue.1.borrow_mut();
                 while let Some((frontier, sent)) = borrow.pop_front() {
 
                     // if data are associated, send em!
@@ -302,10 +312,7 @@ where T: Lattice+Ord+Clone+'static, Tr: TraceReader<K,V,T,R> {
             }
         });
 
-        Arranged {
-            stream: collection,
-            trace: self.clone(),
-        }
+        Arranged { stream, trace }
     }
 }
 
diff --git a/tests/trace.rs b/tests/trace.rs
index ed704d5956..54191c69c6 100644
--- a/tests/trace.rs
+++ b/tests/trace.rs
@@ -17,7 +17,7 @@ pub type OrdValSpine<K, V, T, R> = Spine<K, V, T, R, Rc<OrdValBatch<K, V, T, R>>
 type IntegerTrace = OrdValSpine<UnsignedWrapper<u64>, u64, usize, i64>;
 
 fn get_trace() -> Spine<UnsignedWrapper<u64>, u64, usize, i64, Rc<OrdValBatch<UnsignedWrapper<u64>, u64, usize, i64>>> {
-    let op_info = OperatorInfo::new(0, 0);
+    let op_info = OperatorInfo::new(0, 0, &[]);
     let mut trace = IntegerTrace::new(op_info, None);
     {
         let mut batcher = <<